diff --git a/.gitignore b/.gitignore
index 55e0bc4..32df578 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,5 +4,4 @@
 .env
 .env.*
 /vendor/
-/composer.lock
 *.log
diff --git a/Api/Admin.php b/Api/Admin.php
index d7420a1..07b00fe 100644
--- a/Api/Admin.php
+++ b/Api/Admin.php
@@ -6,12 +6,77 @@ namespace Box\Mod\Mailgateway\Api;
 
 class Admin extends \FOSSBilling\Api\AbstractApi
 {
-    public function ping(array $data): array
+    public function settings_get(array $data): array
     {
+        if (!$this->getIdentity() instanceof \Model_Admin) {
+            throw new \FOSSBilling\InformationException('Administrator authentication required');
+        }
+        $this->checkPermissions('mailgateway', 'manage_settings');
         return [
-            'status' => 'ok',
-            'module' => 'mailgateway',
-            'version' => '0.1.0',
+            'settings' => $this->getService()->getSettings(),
+            'dependencies' => $this->getService()->getDependencyStatus(),
+            'notifications' => $this->getService()->getNotificationStatus(),
+            'mailboxes' => $this->getService()->getMailboxes(),
+            'helpdesks' => $this->getDi()['mod_service']('support')->getHelpdeskRepository()->getPairs(),
         ];
     }
+
+    public function settings_save(array $data): bool
+    {
+        if (!$this->getIdentity() instanceof \Model_Admin) {
+            throw new \FOSSBilling\InformationException('Administrator authentication required');
+        }
+        $this->checkPermissions('mailgateway', 'manage_settings');
+        return $this->getService()->saveSettings($data);
+    }
+
+    public function test_connection(array $data): array
+    {
+        if (!$this->getIdentity() instanceof \Model_Admin) {
+            throw new \FOSSBilling\InformationException('Administrator authentication required');
+        }
+        $this->checkPermissions('mailgateway', 'manage_settings');
+        return $this->getService()->testConnection($data);
+    }
+
+    public function install_dependencies(array $data): array
+    {
+        if (!$this->getIdentity() instanceof \Model_Admin) {
+            throw new \FOSSBilling\InformationException('Administrator authentication required');
+        }
+        $this->checkPermissions('mailgateway', 'manage_settings');
+        $force = $data['force'] ?? false;
+        if (!in_array($force, [true, false, 0, 1, '0', '1'], true)) {
+            throw new \FOSSBilling\InformationException('Invalid dependency installation option');
+        }
+        return $this->getService()->installDependencies(in_array($force, [true, 1, '1'], true));
+    }
+
+    public function setup(array $data): bool
+    {
+        if (!$this->getIdentity() instanceof \Model_Admin) {
+            throw new \FOSSBilling\InformationException('Administrator authentication required');
+        }
+        $this->checkPermissions('mailgateway', 'manage_settings');
+        return $this->getService()->setup();
+    }
+
+    public function notifications_setup(array $data): array
+    {
+        if (!$this->getIdentity() instanceof \Model_Admin) {
+            throw new \FOSSBilling\InformationException('Administrator authentication required');
+        }
+        $this->checkPermissions('mailgateway', 'manage_settings');
+        return $this->getService()->configureNotifications();
+    }
+
+    public function mailbox_delete(array $data): bool
+    {
+        if (!$this->getIdentity() instanceof \Model_Admin) {
+            throw new \FOSSBilling\InformationException('Administrator authentication required');
+        }
+        $this->checkPermissions('mailgateway', 'manage_settings');
+        return $this->getService()->deleteMailbox($data);
+    }
+
 }
diff --git a/DependencyInstaller.php b/DependencyInstaller.php
new file mode 100644
index 0000000..f2e811e
--- /dev/null
+++ b/DependencyInstaller.php
@@ -0,0 +1,111 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use FOSSBilling\InformationException;
+
+class DependencyInstaller
+{
+    public function status(): array
+    {
+        return ['installed' => $this->installed(), 'available' => function_exists('proc_open')
+            && $this->php() !== null && $this->composer() !== null && is_writable(__DIR__),
+            'request_timeout_ms' => (RuntimeConfig::get('composer_timeout_seconds') + 30) * 1000];
+    }
+
+    public function install(bool $force = false): array
+    {
+        if (!$force && $this->installed()) {
+            return ['installed' => true];
+        }
+        $php = $this->php();
+        $composer = $this->composer();
+        if (!function_exists('proc_open') || $php === null || $composer === null || !is_writable(__DIR__)) {
+            throw new InformationException('Web installation is unavailable. Run composer install from the Mailgateway directory using SSH.');
+        }
+        if (!is_file(__DIR__ . '/composer.lock')) {
+            throw new InformationException('The module composer.lock is missing. Restore it before installing dependencies.');
+        }
+        $command = [$php, $composer, 'install', '--no-dev', '--prefer-dist', '--no-interaction',
+            '--no-progress', '--no-scripts', '--no-plugins', '--optimize-autoloader'];
+        $result = $this->run($command);
+        if ($result['timeout']) {
+            throw new InformationException('Dependency installation exceeded its configured timeout. Run composer install from the Mailgateway directory using SSH.');
+        }
+        if ($result['exit'] !== 0 || !$this->installed()) {
+            throw new InformationException('Composer installation failed. Run composer install from the Mailgateway directory using SSH to see the detailed error.');
+        }
+        return ['installed' => true];
+    }
+
+    private function installed(): bool
+    {
+        return is_file(__DIR__ . '/vendor/autoload.php')
+            && is_file(__DIR__ . '/vendor/webklex/php-imap/src/ClientManager.php');
+    }
+
+    private function php(): ?string
+    {
+        foreach (RuntimeConfig::get('php_cli_paths') as $path) {
+            if (is_file($path) && is_executable($path)) {
+                return $path;
+            }
+        }
+        return null;
+    }
+
+    private function composer(): ?string
+    {
+        foreach (RuntimeConfig::get('composer_paths') as $path) {
+            if (is_file($path) && is_readable($path)) {
+                return $path;
+            }
+        }
+        return null;
+    }
+
+    protected function run(array $command): array
+    {
+        // PHP may terminate a web request before Composer completes otherwise.
+        @set_time_limit(RuntimeConfig::get('composer_timeout_seconds') + 15);
+        $process = proc_open($command, [['pipe', 'r'], ['pipe', 'w'], ['pipe', 'w']], $pipes, __DIR__);
+        if (!is_resource($process)) {
+            throw new InformationException('Composer could not be started. Run composer install using SSH.');
+        }
+        fclose($pipes[0]);
+        stream_set_blocking($pipes[1], false);
+        stream_set_blocking($pipes[2], false);
+        $deadline = microtime(true) + RuntimeConfig::get('composer_timeout_seconds');
+        $exit = -1;
+        $timeout = false;
+        try {
+            while (true) {
+                // Drain both pipes to avoid deadlock. Never expose Composer output:
+                // repository authentication and environment details can appear there.
+                stream_get_contents($pipes[1]);
+                stream_get_contents($pipes[2]);
+                $status = proc_get_status($process);
+                if (!$status['running']) {
+                    $exit = $status['exitcode'];
+                    break;
+                }
+                if (microtime(true) >= $deadline) {
+                    $timeout = true;
+                    proc_terminate($process, 9);
+                    break;
+                }
+                usleep(100000);
+            }
+        } finally {
+            fclose($pipes[1]);
+            fclose($pipes[2]);
+            $closed = proc_close($process);
+            if ($exit === -1) {
+                $exit = $closed;
+            }
+        }
+        return ['exit' => $exit, 'timeout' => $timeout];
+    }
+}
diff --git a/ImapConnectionTest.php b/ImapConnectionTest.php
new file mode 100644
index 0000000..46ce93c
--- /dev/null
+++ b/ImapConnectionTest.php
@@ -0,0 +1,112 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use FOSSBilling\InformationException;
+
+class ImapConnectionTest
+{
+    public function __construct(private ?\Closure $factory = null) {}
+
+    public function test(array $settings, bool $createFolders = false): array
+    {
+        if ($settings['password'] === '') {
+            throw new InformationException('Save a mailbox password before testing the connection');
+        }
+        $client = null;
+        $connected = false;
+        $moveSupported = null;
+        $folders = [];
+        $errors = [];
+        try {
+            if ($this->factory === null) {
+                if (!is_file(__DIR__ . '/vendor/autoload.php')) {
+                    throw new InformationException('Install the Mail Gateway Composer dependencies first');
+                }
+                require_once __DIR__ . '/vendor/autoload.php';
+            }
+            $config = [
+                'host' => $settings['host'], 'port' => (int) $settings['port'],
+                'protocol' => 'imap', 'encryption' => $settings['encryption'],
+                'validate_cert' => true, 'username' => $settings['username'],
+                'password' => $settings['password'], 'authentication' => null,
+                'timeout' => RuntimeConfig::get('imap_timeout_seconds'),
+            ];
+            $client = $this->factory !== null ? ($this->factory)($config)
+                : (new \Webklex\PHPIMAP\ClientManager(['options' => ['debug' => false]]))->make($config);
+            $client->connect();
+            $connected = true;
+            try {
+                $capabilities = $client->getConnection()->getCapabilities()->validatedData();
+                $moveSupported = in_array('MOVE', array_map('strtoupper', $capabilities), true);
+                if (!$moveSupported) {
+                    $errors[] = 'IMAP login succeeded, but the server does not support native MOVE. Importing requires MOVE to archive individual messages safely.';
+                }
+            } catch (\Throwable) {
+                $errors[] = 'IMAP login succeeded, but checking server MOVE support failed. Check server access and try again.';
+            }
+            $paths = $this->paths($client);
+            foreach (['inbox_folder', 'processed_folder', 'ignored_folder', 'failed_folder'] as $field) {
+                $path = $settings[$field];
+                $exists = $this->exists($path, $paths);
+                $created = false;
+                $error = null;
+                if (!$exists && $field === 'inbox_folder') {
+                    $error = 'The configured inbox does not exist. Correct its path or create it on the mail server.';
+                } elseif (!$exists && $createFolders) {
+                    try {
+                        // Never expunge messages while creating a destination folder.
+                        $client->createFolder($path, false);
+                    } catch (\Throwable) {
+                        $error = 'Folder creation failed. Check the folder path, parent folders, and mailbox permissions or quota.';
+                    }
+                    if ($error === null) {
+                        try {
+                            $paths = $this->paths($client);
+                            $exists = $this->exists($path, $paths);
+                            $created = $exists;
+                            if (!$exists) {
+                                $error = 'The server accepted folder creation, but the folder could not be found afterwards.';
+                            }
+                        } catch (\Throwable) {
+                            $error = 'The folder creation request completed, but listing folders to verify it failed. Check server access and try again.';
+                        }
+                    }
+                } elseif (!$exists) {
+                    $error = 'The configured destination folder does not exist.';
+                }
+                $folders[] = ['path' => $path, 'exists' => $exists, 'created' => $created, 'error' => $error];
+            }
+        } catch (\Throwable) {
+            // Never return IMAP exception messages or traces (may contain credentials).
+            $errors[] = $connected
+                ? 'IMAP login succeeded, but listing folders failed. Check mailbox permissions and server access.'
+                : 'IMAP connection or login failed. Check the saved host, port, security, username, password, TLS certificate, and network access.';
+        } finally {
+            if ($client !== null) {
+                try { $client->disconnect(); } catch (\Throwable) {}
+            }
+        }
+        $success = $connected && $errors === [] && count($folders) === 4
+            && array_filter($folders, fn ($folder) => !$folder['exists'] || $folder['error'] !== null) === [];
+        return ['success' => $success, 'connected' => $connected, 'move_supported' => $moveSupported, 'folders' => $folders, 'errors' => $errors];
+    }
+
+    private function paths(object $client): array
+    {
+        $paths = [];
+        foreach ($client->getFolders(false) as $folder) {
+            $paths[] = $folder->path;
+            $paths[] = $folder->full_name ?? $folder->path;
+        }
+        return $paths;
+    }
+
+    private function exists(string $path, array $paths): bool
+    {
+        return in_array($path, $paths, true)
+            || (strcasecmp($path, 'INBOX') === 0 && in_array('INBOX', array_map('strtoupper', $paths), true));
+    }
+}
diff --git a/ImapMailbox.php b/ImapMailbox.php
new file mode 100644
index 0000000..4114e29
--- /dev/null
+++ b/ImapMailbox.php
@@ -0,0 +1,147 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use FOSSBilling\InformationException;
+use Webklex\PHPIMAP\IMAP;
+
+/** IMAP transport; deliberately never uses Webklex's MOVE fallback (global EXPUNGE). */
+class ImapMailbox
+{
+    private $client;
+    private $inbox;
+    private array $folders = [];
+
+    public function __construct(private array $settings, private ?\Closure $factory = null) {}
+
+    public function connect(): void
+    {
+        if ($this->settings['password'] === '') {
+            throw new InformationException('Mailbox password is missing');
+        }
+        if ($this->factory === null) {
+            if (!is_file(__DIR__ . '/vendor/autoload.php')) {
+                throw new InformationException('Mail Gateway Composer dependencies are missing');
+            }
+            require_once __DIR__ . '/vendor/autoload.php';
+        }
+        $config = [
+            'host' => $this->settings['host'], 'port' => (int) $this->settings['port'],
+            'protocol' => 'imap', 'encryption' => $this->settings['encryption'],
+            'validate_cert' => true, 'username' => $this->settings['username'],
+            'password' => $this->settings['password'], 'authentication' => null, 'timeout' => RuntimeConfig::get('imap_timeout_seconds'),
+        ];
+        $this->client = $this->factory !== null ? ($this->factory)($config)
+            : (new \Webklex\PHPIMAP\ClientManager(['options' => ['debug' => false]]))->make($config);
+        $this->client->connect();
+        $capabilities = $this->client->getConnection()->getCapabilities()->validatedData();
+        if (!in_array('MOVE', array_map('strtoupper', $capabilities), true)) {
+            throw new InformationException('IMAP server must support MOVE');
+        }
+        foreach (['inbox_folder', 'processed_folder', 'ignored_folder', 'failed_folder'] as $field) {
+            $folder = $this->client->getFolderByPath($this->settings[$field]);
+            if ($folder === null || $folder->no_select) {
+                throw new InformationException('A configured IMAP folder is missing or cannot be selected');
+            }
+            $this->folders[$field] = $folder;
+        }
+        $this->inbox = $this->folders['inbox_folder'];
+    }
+
+    public function uids(int $limit): array
+    {
+        $query = $this->inbox->query()->leaveUnread()->setSequence(IMAP::ST_UID)->whereUndeleted();
+        $uids = array_map('intval', $query->search()->toArray());
+        sort($uids, SORT_NUMERIC);
+        return array_slice($uids, 0, $limit);
+    }
+
+    public function read(int $uid): array
+    {
+        $message = $this->inbox->query()->leaveUnread()->fetchBody(false)->setFetchFlags(false)->getMessageByUid($uid);
+        $header = $message->getHeader();
+        $headers = self::rawHeaders($header->raw);
+        $policy = new InboundPolicy();
+        $ignored = $policy->ignoreReason($policy->headers(['headers' => $headers])) !== null;
+        if (!$ignored) {
+            if ((int) $message->getSize() > RuntimeConfig::get('max_message_bytes')) {
+                throw new InformationException('Email exceeds the configured import size limit');
+            }
+            // Webklex parseBody() fetches RFC822.TEXT then restores Seen flags.
+            // Fetch with true PEEK instead: even a crash cannot mark mail as read.
+            $bodies = $this->client->getConnection()->fetch(['BODY.PEEK[TEXT]', 'UID'], [$uid], null, IMAP::ST_UID)->validatedData();
+            $body = $bodies[$uid]['BODY[TEXT]'] ?? null;
+            if (!is_string($body)) {
+                throw new \RuntimeException('IMAP body was not returned');
+            }
+            $message->parseRawBody($body);
+        }
+        return self::data($message, $this->settings['mailbox'], $headers, $ignored);
+    }
+
+    /** Keep repeated values and the literal null Return-Path lost by address parsers. */
+    public static function rawHeaders(string $raw): array
+    {
+        $raw = preg_replace('/\r?\n[ \t]+/', ' ', $raw);
+        $headers = [];
+        foreach (preg_split('/\r?\n/', $raw) as $line) {
+            if (preg_match('/^([A-Za-z0-9-]+):[ \t]*(.*)$/D', $line, $match)) {
+                $headers[strtolower($match[1])][] = trim($match[2]);
+            }
+        }
+        return $headers;
+    }
+
+    public static function data(object $message, string $mailbox, array $headers, bool $ignored): array
+    {
+        $ids = $headers['message-id'] ?? [];
+        if (count($ids) > 1) {
+            throw new InformationException('Email has multiple Message-ID headers');
+        }
+        // A stable MIME fingerprint also deduplicates messages without a Message-ID.
+        $id = $ids[0] ?? '<' . hash('sha256', $message->getHeader()->raw . ($ignored ? '' : $message->getRawBody())) . '@mailgateway.invalid>';
+        $data = ['mailbox' => $mailbox, 'message_id' => $id, 'headers' => $headers];
+        if ($ignored) {
+            return $data;
+        }
+        $senders = $message->getFrom()->toArray();
+        if (count($headers['from'] ?? []) !== 1 || count($senders) !== 1) {
+            throw new InformationException('Email must have exactly one From address');
+        }
+        $sender = $senders[0];
+        $content = trim($message->getTextBody());
+        if ($content === '') {
+            $html = preg_replace('/<(script|style)\b[^>]*>.*?<\/\1\s*>/is', '', $message->getHTMLBody());
+            $html = preg_replace('/<br\s*\/?\s*>|<\/(?:p|div|li|tr|h[1-6])\s*>/i', "\n", $html);
+            $content = trim(html_entity_decode(strip_tags($html), ENT_QUOTES | ENT_HTML5, 'UTF-8'));
+        }
+        $subject = trim(mb_decode_mimeheader((string) $message->getSubject()));
+        return $data + [
+            'sender_email' => $sender->mail,
+            'sender_name' => trim(mb_decode_mimeheader($sender->personal)) ?: $sender->mail,
+            'subject' => $subject === '' ? '(No subject)' : $subject,
+            'content' => $content,
+        ];
+    }
+
+    public function move(int $uid, string $destination): void
+    {
+        $this->client->openFolder($this->inbox->path);
+        $protocol = $this->client->getConnection();
+        // Native UID MOVE touches only this message. No COPY/STORE/EXPUNGE fallback.
+        $response = $protocol->requestAndResponse('UID MOVE', [(string) $uid,
+            $protocol->escapeString($this->folders[$destination]->path)], true);
+        if (!$response->boolean()) {
+            throw new \RuntimeException('IMAP MOVE failed');
+        }
+    }
+
+    public function disconnect(): void
+    {
+        if ($this->client !== null) {
+            $this->client->disconnect();
+        }
+    }
+}
diff --git a/InboundPolicy.php b/InboundPolicy.php
new file mode 100644
index 0000000..69f2ca7
--- /dev/null
+++ b/InboundPolicy.php
@@ -0,0 +1,101 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use FOSSBilling\InformationException;
+
+class InboundPolicy
+{
+    private const FIELDS = [
+        'auto-submitted', 'precedence', 'return-path', 'content-type',
+        'x-auto-response-suppress', 'x-autoreply', 'x-autorespond', 'list-id',
+    ];
+
+    /** Normalize parsed MIME headers and supported flat header fields. */
+    public function headers(array $data): array
+    {
+        $raw = $data['headers'] ?? [];
+        if (!is_array($raw)) {
+            throw new InformationException('headers must be an array of header values');
+        }
+        foreach (self::FIELDS as $field) {
+            $flat = str_replace('-', '_', $field);
+            if (array_key_exists($flat, $data)) {
+                $raw[$field] = array_merge((array) ($raw[$field] ?? []), (array) $data[$flat]);
+            }
+        }
+        $headers = [];
+        foreach ($raw as $name => $values) {
+            if (!is_string($name)) {
+                throw new InformationException('Header names must be strings');
+            }
+            $name = strtolower(str_replace('_', '-', $name));
+            if (!in_array($name, self::FIELDS, true)) {
+                continue;
+            }
+            $values = is_array($values) ? $values : [$values];
+            if (count($values) > 20) {
+                throw new InformationException('Too many repeated header values');
+            }
+            foreach ($values as $value) {
+                if (!is_string($value) || strlen($value) > 16384) {
+                    throw new InformationException('Header values must be strings of at most 16384 bytes');
+                }
+                $value = preg_replace('/\r?\n[ \t]+/', ' ', $value);
+                if (preg_match('/[\x00-\x08\x0A-\x1F\x7F]/', $value)) {
+                    throw new InformationException('Invalid control character in header value');
+                }
+                $headers[$name][] = strtolower(trim($value));
+            }
+        }
+        ksort($headers);
+
+        return $headers;
+    }
+
+    public function ignoreReason(array $headers): ?string
+    {
+        foreach ($headers['auto-submitted'] ?? [] as $value) {
+            if (trim(explode(';', $value, 2)[0]) !== 'no') {
+                return 'auto_submitted';
+            }
+        }
+        foreach ($headers['return-path'] ?? [] as $value) {
+            if (preg_match('/^<\s*>$/D', $value)) {
+                return 'null_return_path';
+            }
+        }
+        foreach ($headers['content-type'] ?? [] as $value) {
+            if (preg_match('/^multipart\/report\s*(?:;|$)/', $value)
+                || preg_match('/^message\/(?:delivery-status|disposition-notification|global-delivery-status)\s*(?:;|$)/', $value)) {
+                return 'delivery_report';
+            }
+        }
+        foreach ($headers['precedence'] ?? [] as $value) {
+            if (in_array(trim(explode(';', $value, 2)[0]), ['bulk', 'list', 'junk'], true)) {
+                return 'bulk_mail';
+            }
+        }
+        foreach ($headers['list-id'] ?? [] as $value) {
+            if ($value !== '') {
+                return 'mailing_list';
+            }
+        }
+        foreach ($headers['x-auto-response-suppress'] ?? [] as $value) {
+            if (preg_match('/(?:^|[\s,;])(?:all|autoreply|oof|dr|ndr|rn|nrn)(?:$|[\s,;])/', $value)) {
+                return 'response_suppressed';
+            }
+        }
+        foreach (['x-autoreply', 'x-autorespond'] as $field) {
+            foreach ($headers[$field] ?? [] as $value) {
+                if (!in_array($value, ['', 'no', 'false', '0'], true)) {
+                    return 'legacy_autoresponder';
+                }
+            }
+        }
+
+        return null;
+    }
+}
diff --git a/MessageTracker.php b/MessageTracker.php
new file mode 100644
index 0000000..21fa447
--- /dev/null
+++ b/MessageTracker.php
@@ -0,0 +1,146 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use Doctrine\DBAL\Connection;
+use Doctrine\DBAL\Exception\UniqueConstraintViolationException;
+use FOSSBilling\InformationException;
+
+class MessageTracker
+{
+    public function __construct(private Connection $connection) {}
+
+    public function process(array $data, Service $service): array
+    {
+        $mailbox = $this->mailbox($data);
+        $messageId = $this->messageId($data['message_id'] ?? null);
+        $policy = new InboundPolicy();
+        $headers = $policy->headers($data);
+        $ignoreReason = $policy->ignoreReason($headers);
+        $ticketId = $ignoreReason === null ? $this->subjectTicketId($data['subject'] ?? null) : null;
+        // Hash only accepted inputs, independent of request field order.
+        $payload = [];
+        foreach (['sender_email', 'sender_name', 'subject', 'content'] as $field) {
+            $value = $data[$field] ?? null;
+            if ($value !== null && !is_string($value)) {
+                throw new InformationException($field . ' must be a string');
+            }
+            $payload[$field] = $value;
+        }
+        $payload['parents'] = []; // Preserve fingerprints of earlier new-ticket imports.
+        if ($headers !== []) {
+            $payload['headers'] = $headers;
+        }
+        $hash = hash('sha256', json_encode($payload, JSON_THROW_ON_ERROR));
+        $key = $this->key($mailbox, $messageId);
+        $this->assertStandaloneTransaction();
+        $this->connection->beginTransaction();
+        try {
+            $this->connection->insert('mailgateway_message', [
+                'message_key' => $key, 'mailbox' => $mailbox, 'message_id' => $messageId,
+                'payload_hash' => $hash,
+            ]);
+        } catch (UniqueConstraintViolationException) {
+            $this->connection->rollBack();
+            $row = $this->connection->fetchAssociative('SELECT * FROM mailgateway_message WHERE message_key = ?', [$key]);
+            if (!$row || $row['payload_hash'] !== $hash || !$row['result_json']) {
+                throw new InformationException('Message-ID is already registered with different contents');
+            }
+            return array_merge(json_decode($row['result_json'], true, 512, JSON_THROW_ON_ERROR), ['duplicate' => true]);
+        } catch (\Throwable $error) {
+            $this->connection->rollBack();
+            throw $error;
+        }
+
+        try {
+            if ($ignoreReason !== null) {
+                $result = ['action' => 'ignored', 'reason' => $ignoreReason];
+            } elseif ($ticketId !== null) {
+                $data['ticket_id'] = $ticketId;
+                $result = $service->reply($data);
+                $result['action'] = 'reply';
+            } else {
+                $result = $service->import($data);
+                $result['action'] = 'ticket';
+            }
+            $result['duplicate'] = false;
+            $this->connection->update('mailgateway_message', [
+                'ticket_id' => $result['ticket_id'] ?? null,
+                'result_json' => json_encode($result, JSON_THROW_ON_ERROR),
+            ], ['message_key' => $key]);
+            $this->connection->commit();
+            return $result;
+        } catch (\Throwable $error) {
+            if ($this->connection->isTransactionActive()) {
+                $this->connection->rollBack();
+            }
+            // Drop entities whose writes were rolled back, including queued mail.
+            $service->getDi()['em']->clear();
+            // Queue rejection notifications only after the import has rolled back.
+            if ($error instanceof InformationException && in_array($error->getMessage(), [
+                'Sender does not own this ticket', 'Sender does not uniquely match the ticket owner',
+            ], true)) {
+                $service->notifySenderMismatch($data['sender_email'], (int) $data['ticket_id']);
+            }
+            throw $error;
+        }
+    }
+
+    private function subjectTicketId(mixed $subject): ?int
+    {
+        if (!is_string($subject) || trim($subject) === '' || strlen($subject) > 998
+            || !mb_check_encoding($subject, 'UTF-8') || preg_match('/[\x00-\x1F\x7F]/', $subject)) {
+            throw new InformationException('A non-empty UTF-8 subject without control characters is required (maximum 998 bytes)');
+        }
+        preg_match_all('/\[Ticket\b[^\]]*\]/i', $subject, $matches);
+        if (preg_match('/\[Ticket\b/i', str_replace($matches[0], '', $subject))) {
+            throw new InformationException('Incomplete ticket reference in subject');
+        }
+        $ids = [];
+        foreach ($matches[0] as $reference) {
+            if (!preg_match('/^\[Ticket #([1-9][0-9]*)\]$/iD', $reference, $match)
+                || filter_var($match[1], FILTER_VALIDATE_INT, ['options' => ['min_range' => 1]]) === false) {
+                throw new InformationException('Invalid ticket reference in subject; expected [Ticket #123]');
+            }
+            $ids[(int) $match[1]] = true;
+        }
+        if (count($ids) > 1) {
+            throw new InformationException('Subject refers to multiple tickets');
+        }
+
+        return $ids ? array_key_first($ids) : null;
+    }
+
+    private function assertStandaloneTransaction(): void
+    {
+        if ($this->connection->isTransactionActive()) {
+            throw new \LogicException('Tracked import requires its own transaction');
+        }
+    }
+
+    private function mailbox(array $data): string
+    {
+        $mailbox = $data['mailbox'] ?? null;
+        if (!is_string($mailbox) || strlen($mailbox) > 255 || !filter_var($mailbox, FILTER_VALIDATE_EMAIL)) {
+            throw new InformationException('A valid mailbox address is required');
+        }
+        return strtolower($mailbox);
+    }
+
+    private function messageId(mixed $value): string
+    {
+        if (!is_string($value) || strlen($value) > 998
+            || !preg_match('/^<[^<>\s@]+@[^<>\s@]+>$/D', $value)
+            || preg_match('/[^\x21-\x7E]/', $value)) {
+            throw new InformationException('Message-ID must be a single ASCII <id@domain> value');
+        }
+        return $value;
+    }
+
+    private function key(string $mailbox, string $messageId): string
+    {
+        return hash('sha256', $mailbox . "\0" . $messageId);
+    }
+}
diff --git a/NotificationCooldown.php b/NotificationCooldown.php
new file mode 100644
index 0000000..d04ac69
--- /dev/null
+++ b/NotificationCooldown.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use Doctrine\DBAL\Connection;
+use Doctrine\DBAL\Exception\UniqueConstraintViolationException;
+
+class NotificationCooldown
+{
+    private int $seconds;
+
+    public function __construct(private Connection $connection, ?int $seconds = null)
+    {
+        $this->seconds = $seconds ?? RuntimeConfig::get('notification_cooldown_seconds');
+    }
+
+    /** Atomically reserve a sender's notification slot and queue the email. */
+    public function run(string $sender, callable $queue): bool
+    {
+        $key = hash('sha256', strtolower(trim($sender)));
+        $now = time();
+
+        return $this->connection->transactional(function () use ($key, $now, $queue): bool {
+            try {
+                $this->connection->insert('mailgateway_notification', ['sender_key' => $key, 'last_notified_at' => 0]);
+            } catch (UniqueConstraintViolationException) {
+                // Existing sender; the conditional update decides who owns the slot.
+            }
+            $claimed = $this->connection->executeStatement(
+                'UPDATE mailgateway_notification SET last_notified_at = ? WHERE sender_key = ? AND last_notified_at <= ?',
+                [$now, $key, $now - $this->seconds],
+            );
+            if ($claimed !== 1) {
+                return false;
+            }
+            if ($queue() === false) {
+                // Disabled templates do not consume the sender's notification slot.
+                $this->connection->delete('mailgateway_notification', ['sender_key' => $key]);
+                return false;
+            }
+
+            return true;
+        });
+    }
+}
diff --git a/NotificationEmailProxy.php b/NotificationEmailProxy.php
new file mode 100644
index 0000000..4cd9526
--- /dev/null
+++ b/NotificationEmailProxy.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+/** Used only while Support creates a ticket for an imported message. */
+class NotificationEmailProxy
+{
+    public function __construct(private object $email, private \Closure $acknowledge) {}
+
+    public function sendTemplate(array $data): mixed
+    {
+        if (($data['code'] ?? '') === 'mod_support_ticket_open') {
+            return ($this->acknowledge)($data);
+        }
+        // The canned reply remains in the ticket. Send the ticket-number
+        // acknowledgement instead of a second automatic canned-reply email.
+        if (($data['code'] ?? '') === 'mod_support_ticket_staff_reply') {
+            return false;
+        }
+
+        return $this->email->sendTemplate($data);
+    }
+
+    public function __call(string $method, array $arguments): mixed
+    {
+        return $this->email->$method(...$arguments);
+    }
+}
diff --git a/NotificationSettings.php b/NotificationSettings.php
new file mode 100644
index 0000000..962bca4
--- /dev/null
+++ b/NotificationSettings.php
@@ -0,0 +1,76 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use Pimple\Container;
+
+class NotificationSettings
+{
+    private const CODES = ['mod_support_ticket_open', 'mod_support_ticket_staff_reply',
+        'mod_support_ticket_staff_open', 'mod_support_ticket_staff_close'];
+
+    public function __construct(private Container $di) {}
+
+    private function hasMarker(string $subject): bool
+    {
+        return (bool) preg_match('/\[Ticket\s+#\s*{{\s*ticket\.id\s*}}\s*\]/i', $subject);
+    }
+
+    public function repair(): array
+    {
+        $email = $this->di['mod_service']('email');
+        foreach (self::CODES as $code) {
+            $template = $email->getTemplateRepository()->findOneByActionCode($code);
+            if ($template === null) {
+                $source = file_get_contents(dirname(__DIR__) . '/Support/templates/email/' . $code . '.html.twig');
+                if (!is_string($source)
+                    || !preg_match('/{%\s*block subject\s*%}(.*?){%\s*endblock\s*%}/s', $source, $subject)
+                    || !preg_match('/{%\s*block content\s*%}(.*?){%\s*endblock\s*%}/s', $source, $content)) {
+                    throw new \FOSSBilling\InformationException("Cannot configure $code: its default template is missing or invalid.");
+                }
+                $template = $email->templateCreate($code, trim($subject[1]), trim($content[1]),
+                    $code === 'mod_support_ticket_open' ? 1 : 0, 'support');
+            }
+            $data = $email->templateToApiArray($template);
+            if ($code !== 'mod_support_ticket_open' && !$data['enabled']) {
+                continue;
+            }
+            $subject = $data['subject'] ?? '';
+            $enabled = $code === 'mod_support_ticket_open' ? true : null;
+            if (!$this->hasMarker($subject)) {
+                // Keep the existing subject and body, adding only the routing marker.
+                $email->updateTemplate($template, $enabled, null, '[Ticket #{{ ticket.id }}] ' . $subject);
+            } elseif ($code === 'mod_support_ticket_open' && !$data['enabled']) {
+                $email->updateTemplate($template, true);
+            }
+        }
+        return $this->status();
+    }
+
+    public function status(): array
+    {
+        $email = $this->di['mod_service']('email');
+        $errors = [];
+        foreach (self::CODES as $code) {
+            $template = $email->getTemplateRepository()->findOneByActionCode($code);
+            if ($template === null) {
+                $errors[] = "Open FOSSBilling Email settings and configure $code before enabling importing.";
+                continue;
+            }
+            $data = $email->templateToApiArray($template);
+            if (!$data['enabled']) {
+                if ($code === 'mod_support_ticket_open') {
+                    $errors[] = 'Enable mod_support_ticket_open in FOSSBilling Email settings to send ticket acknowledgements.';
+                }
+                continue;
+            }
+            // Check the documented dynamic marker without executing custom template code.
+            if (!$this->hasMarker($data['subject'] ?? '')) {
+                $errors[] = "Include [Ticket #{{ ticket.id }}] in the subject of $code in FOSSBilling Email settings.";
+            }
+        }
+        return ['ready' => $errors === [], 'errors' => $errors];
+    }
+}
diff --git a/Poller.php b/Poller.php
new file mode 100644
index 0000000..107c0c4
--- /dev/null
+++ b/Poller.php
@@ -0,0 +1,138 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use FOSSBilling\InformationException;
+use Pimple\Container;
+
+class Poller
+{
+    private const LOCK = 'fossbilling_mailgateway_poll';
+
+    public function __construct(
+        private Container $di,
+        private Service $service,
+        private ?\Closure $factory = null,
+        private ?\Closure $clock = null,
+        private ?\Closure $lock = null,
+    ) {}
+
+    public function poll(bool $force = false): array
+    {
+        if (!$this->locking(true)) {
+            return ['status' => 'busy', 'mailboxes' => []];
+        }
+        try {
+            $store = $this->di['mailgateway_settings'] ?? new Settings($this->di);
+            $mailboxes = array_filter($store->getAll(), fn ($settings) => $settings['enabled']);
+            if ($mailboxes === []) {
+                return ['status' => 'disabled', 'mailboxes' => []];
+            }
+            $system = $this->di['mod_service']('system');
+            $now = $this->now();
+            $last = (int) $system->getParamValue('mailgateway_last_poll', 0);
+            if (!$force && $last > $now - RuntimeConfig::get('poll_interval_seconds')) {
+                return ['status' => 'not_due', 'mailboxes' => []];
+            }
+            // Record the attempt before network work, so a failing server is not hammered.
+            $system->setParamValue('mailgateway_last_poll', (string) $now, true);
+            $results = [];
+            $deadline = microtime(true) + RuntimeConfig::get('poll_budget_seconds');
+            foreach ($mailboxes as $id => $settings) {
+                if (microtime(true) >= $deadline) {
+                    break;
+                }
+                $results[$id] = $this->mailbox($id, $settings, $deadline);
+            }
+            return ['status' => 'completed', 'mailboxes' => $results];
+        } finally {
+            $this->locking(false);
+        }
+    }
+
+    private function mailbox(string $id, array $settings, float $deadline): array
+    {
+        $counts = ['ticket' => 0, 'reply' => 0, 'ignored' => 0, 'duplicate' => 0, 'failed' => 0, 'retry_pending' => 0, 'move_pending' => 0];
+        $transport = null;
+        $errors = [];
+        $stage = 'connecting';
+        try {
+            $transport = $this->factory !== null ? ($this->factory)($settings) : new ImapMailbox($settings);
+            $transport->connect();
+            $stage = 'listing messages';
+            foreach ($transport->uids(RuntimeConfig::get('messages_per_mailbox')) as $uid) {
+                if (microtime(true) >= $deadline) {
+                    break;
+                }
+                try {
+                    $stage = 'reading email';
+                    $data = $transport->read((int) $uid);
+                    $stage = 'importing email';
+                    $result = (new MessageTracker($this->di['dbal']))->process($data, $this->service);
+                    $counts[$result['duplicate'] ? 'duplicate' : $result['action']]++;
+                    $destination = $result['action'] === 'ignored' ? 'ignored_folder' : 'processed_folder';
+                } catch (InformationException $error) {
+                    $errors[] = $this->diagnostic($error, $stage, (int) $uid);
+                    $counts['failed']++;
+                    $destination = 'failed_folder';
+                    $this->warning($id, (int) $uid, 'message rejected; moving to Failed');
+                } catch (\Throwable $error) {
+                    $errors[] = $this->diagnostic($error, $stage, (int) $uid);
+                    // Infrastructure/fetch failures stay in the inbox for a later attempt.
+                    $counts['retry_pending']++;
+                    $this->warning($id, (int) $uid, 'import unavailable; left in inbox for retry');
+                    continue;
+                }
+                try {
+                    $stage = 'moving email';
+                    $transport->move((int) $uid, $destination);
+                } catch (\Throwable $error) {
+                    $errors[] = $this->diagnostic($error, $stage, (int) $uid);
+                    // Import already committed. Tracking prevents a second ticket on retry.
+                    $counts['move_pending']++;
+                    $this->warning($id, (int) $uid, 'folder move failed; retry will use message tracking');
+                }
+            }
+            return ['status' => 'completed'] + $counts + ($errors === [] ? [] : ['errors' => $errors]);
+        } catch (\Throwable $error) {
+            $errors[] = $this->diagnostic($error, $stage, null);
+            $this->warning($id, null, 'mailbox poll failed; check credentials, TLS, folders, network access, and server MOVE support');
+            return ['status' => 'failed'] + $counts + ['errors' => $errors];
+        } finally {
+            if ($transport !== null) {
+                try { $transport->disconnect(); } catch (\Throwable) {
+                    $this->warning($id, null, 'IMAP logout failed');
+                }
+            }
+        }
+    }
+
+    private function diagnostic(\Throwable $error, string $stage, ?int $uid): array
+    {
+        // A location identifies code faults without exposing exception messages/arguments.
+        return ['uid' => $uid, 'stage' => $stage, 'exception' => $error::class,
+            'file' => basename($error->getFile()), 'line' => $error->getLine()];
+    }
+
+    private function warning(string $id, ?int $uid, string $text): void
+    {
+        // Never log IMAP exception messages/traces, credentials, sender, subject or body.
+        $this->di['logger']->warning('Mail Gateway mailbox ' . $id . ($uid !== null ? ' UID ' . $uid : '') . ': ' . $text);
+    }
+
+    private function now(): int
+    {
+        return $this->clock !== null ? ($this->clock)() : time();
+    }
+
+    private function locking(bool $acquire): bool
+    {
+        if ($this->lock !== null) {
+            return ($this->lock)($acquire);
+        }
+        $sql = $acquire ? 'SELECT GET_LOCK(?, 0)' : 'SELECT RELEASE_LOCK(?)';
+        return (int) $this->di['dbal']->fetchOne($sql, [self::LOCK]) === 1;
+    }
+}
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..4bb9c8f
--- /dev/null
+++ b/README.md
@@ -0,0 +1,190 @@
+# Mail Gateway for FOSSBilling
+
+Mail Gateway imports email into FOSSBilling support tickets using the existing
+FOSSBilling cron. Configure multiple IMAP mailboxes and route each one to a
+separate helpdesk.
+
+## Features
+
+- Create customer tickets from recognised email addresses and guest tickets from unknown senders.
+- Add replies to existing tickets using the ticket number in the subject.
+- Check that the sender owns the ticket before accepting a reply.
+- Filter recognised automatic messages and prevent duplicate imports.
+- Move handled emails into Processed, Ignored or Failed folders.
+- Manage mailbox connections and test them from the admin settings page.
+
+## Requirements
+
+- FOSSBilling with the Support module enabled and its cron running regularly.
+- An IMAP server supporting native `MOVE` and a valid TLS certificate when using TLS.
+- A receiving mail server with appropriate email authentication and anti-spoofing policies.
+- The `webklex/php-imap` Composer package and its required PHP extensions.
+
+The native PHP IMAP extension is not required. Composer checks dependency
+requirements when installing. For installation through the settings page, the
+web server also needs access to PHP CLI, Composer, `proc_open`, a writable module
+directory and package downloads. If web installation is unavailable or the module
+directory is deliberately not writable by the web server, installation over SSH
+is the preferred fallback. Run this from the module directory as its owning user:
+
+```bash
+composer install --no-dev --prefer-dist --no-interaction --no-scripts --no-plugins --optimize-autoloader
+```
+
+This uses the supplied lock file. The web server still needs read access to the
+installed dependencies; it does not need write access to them for importing.
+
+## Installation
+
+1. Place the module in `modules/Mailgateway`.
+2. Activate Mail Gateway in FOSSBilling. Activation creates the module tables,
+   registers its sender-mismatch email template and attempts to install dependencies.
+3. Open Mail Gateway's settings from the Extensions page. If dependencies were
+   not installed automatically, use **Install dependencies** or run
+   `composer install` in the module directory.
+4. Configure the receiving email address, helpdesk, IMAP connection details and
+   inbox and destination folders, then save.
+5. Select **Test Connection and Create Folders**. This verifies the connection
+   and creates missing destination folders without processing emails.
+6. After a successful test, enable mailbox importing and save again. This also
+   configures ticket acknowledgement and notification subjects automatically.
+
+**Notification template changes persist:** enabling importing or running
+**Configure ticket notifications** enables the ticket acknowledgement and adds
+missing ticket references to existing FOSSBilling notification subjects. These
+changes apply to those templates throughout FOSSBilling. Disabling or uninstalling
+Mail Gateway does not restore their original subjects or enabled state. If you
+want to restore them later, keep a copy of the original settings and edit the
+templates manually in FOSSBilling's Email settings.
+
+Use **Add mailbox** to configure additional addresses. Each mailbox has its own
+connection details, folders and helpdesk. All four folder paths must be distinct;
+the inbox must already exist.
+
+Importing remains disabled until dependencies are installed and the mailbox has
+passed its connection and folder test. Changing connection details or folder
+paths requires another successful test. The settings page shows the results and
+explains any failures.
+
+No additional cron entry is needed. The module polls every five minutes by
+default, provided the FOSSBilling cron runs that often.
+
+## Tickets and replies
+
+Email from a customer's primary email address creates a customer ticket.
+Unknown senders create guest tickets when guest tickets are enabled in Support.
+New tickets go to the mailbox's selected helpdesk.
+
+Replies are matched by a subject marker such as `[Ticket #123]`. The sender must
+own the referenced ticket. Emails without a ticket marker create a new ticket;
+reply headers are not used for matching.
+
+Sender matching uses the email's From address; it does not prove that the sender
+controls that address. Mail Gateway does not independently verify SPF, DKIM or
+DMARC, and relies on the receiving mail server to apply authentication and
+anti-spoofing policies before mail reaches the imported inbox. Configure those
+policies to reject or quarantine suspicious messages outside that inbox.
+A forged message accepted into the inbox could impersonate a customer or the
+owner of a guest ticket. Guest reply ownership is based on the original sender's
+email address, without an authenticated customer account.
+
+Enabling mailbox importing automatically enables the `mod_support_ticket_open`
+acknowledgement and adds `[Ticket #{{ ticket.id }}]` to its subject and enabled
+staff notification subjects where missing. Existing wording is preserved and
+disabled optional staff notifications stay disabled. Notifications are delivered
+through FOSSBilling's email queue.
+
+For an existing mailbox, use **Advanced → Configure ticket notifications** to run
+the same setup. Notification status is shown in Advanced, with any problems also
+displayed at the top of the page. Setup does not send test emails. You can edit
+notification wording in FOSSBilling's Email settings; keep the ticket marker in
+subjects so replies can be matched.
+
+The included `mailgateway_sender_mismatch` template uses your company name and
+email signature to tell senders when their address does not match the referenced
+ticket. It is installed only if missing. Its wording can be edited or the
+notification disabled in Email settings. Existing custom templates are preserved.
+
+Messages use plain text when available, with HTML converted to text otherwise.
+Quoted reply history is retained. Attachments stay in the archived email and are
+not attached to tickets.
+
+## Email handling
+
+| Result | Destination |
+| --- | --- |
+| Imported ticket, reply or duplicate | Processed |
+| Recognised automatic message | Ignored |
+| Invalid message or rejected reply | Failed |
+| Temporary connection or database failure | Inbox, for retry |
+
+Only the configured inbox is imported, including already-read messages.
+Duplicate tracking prevents repeated imports, including when a folder move needs
+to be retried. To retry a rejected email after resolving its cause, move it from
+Failed back to the inbox.
+
+Recognised automatic messages receive no response. Unmarked automatic messages
+cannot always be identified; a notification cooldown limits automated
+acknowledgements and sender-mismatch notices to one per sender per hour by default.
+
+## Configuration and maintenance
+
+Mailbox settings are stored in the database, with passwords encrypted using
+FOSSBilling's encryption helper. Leaving a password blank keeps the saved value;
+use the password-clearing option to remove it.
+
+Operational settings are in `config.php`, including polling limits, timeouts,
+message size limits, notification cooldown and executable paths. Edit this file
+over SSH; changes take effect on the next cron run or web request. By default,
+each run handles up to 50 messages per mailbox, with a shared 90-second time
+budget. Complete emails are limited to 5 MiB and ticket bodies to 65,535 bytes.
+
+The settings page's **Advanced** section provides notification setup, Composer
+installation and table setup. Table setup creates missing tables and the default
+mismatch template without deleting existing data or replacing customised templates.
+
+Deleting a mailbox removes its configuration while keeping emails, folders,
+tickets and message tracking.
+
+The following commands are available from the module directory:
+
+```bash
+# Test a saved mailbox without processing emails.
+php tools/test-imap.php
+
+# Test another mailbox and create missing destination folders.
+php tools/test-imap.php --mailbox=billing@example.com --create-folders
+
+# Import mail immediately.
+php tools/poll.php --force
+
+# Create missing tables and register the default email template.
+php tools/setup.php
+```
+
+A connection test with `--create-folders` records the mailbox's readiness, just as
+the settings-page test does. A read-only test does not change readiness.
+
+## Compatibility note
+
+The module loads its own Composer dependencies into the same PHP process as
+FOSSBilling. Shared Symfony or Illuminate packages are not isolated by the module's
+separate `vendor` directory. Check installation, connection testing and importing
+on your FOSSBilling version before deploying; compatibility across clean
+FOSSBilling installations and versions has not yet been established.
+
+During imported ticket creation, the module temporarily wraps FOSSBilling's
+`mod_service` factory to intercept email calls. This applies the acknowledgement
+cooldown and suppresses the separate canned-response email while retaining its
+ticket history. Other module lookups are delegated to the original factory,
+which is restored in a `finally` block, including when creation fails.
+
+Ticket-creation hooks also see this wrapped factory: email services obtained
+during that scope are proxies, and matching notification codes are intercepted.
+The installed FOSSBilling notification interfaces provide no per-ticket
+suppression option. This integration should be reviewed when upgrading
+FOSSBilling or adding hooks that send emails during ticket creation.
+
+## License
+
+Apache-2.0.
diff --git a/RuntimeConfig.php b/RuntimeConfig.php
new file mode 100644
index 0000000..2b1094e
--- /dev/null
+++ b/RuntimeConfig.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+class RuntimeConfig
+{
+    public static function get(string $key): mixed
+    {
+        static $settings = null;
+        $settings ??= self::load(__DIR__ . '/config.php');
+        return $settings[$key] ?? throw new \RuntimeException('Unknown Mail Gateway operational setting: ' . $key);
+    }
+
+    public static function load(string $path): array
+    {
+        $settings = require $path;
+        if (!is_array($settings)) {
+            throw new \RuntimeException('Mail Gateway config.php must return an array');
+        }
+        foreach (['poll_interval_seconds', 'messages_per_mailbox', 'poll_budget_seconds',
+            'imap_timeout_seconds', 'max_message_bytes', 'max_ticket_body_bytes',
+            'notification_cooldown_seconds', 'composer_timeout_seconds'] as $key) {
+            if (!isset($settings[$key]) || !is_int($settings[$key]) || $settings[$key] < 1) {
+                throw new \RuntimeException('Mail Gateway config.php requires a positive integer for ' . $key);
+            }
+        }
+        if ($settings['max_ticket_body_bytes'] > 65535) {
+            throw new \RuntimeException('Mail Gateway ticket body limit cannot exceed 65535 bytes');
+        }
+        foreach (['php_cli_paths', 'composer_paths'] as $key) {
+            if (!isset($settings[$key]) || !is_array($settings[$key]) || $settings[$key] === []) {
+                throw new \RuntimeException('Mail Gateway config.php requires executable paths for ' . $key);
+            }
+            foreach ($settings[$key] as $value) {
+                if (!is_string($value) || !str_starts_with($value, '/') || str_contains($value, "\0")) {
+                    throw new \RuntimeException('Mail Gateway executable paths must be absolute paths');
+                }
+            }
+        }
+        return $settings;
+    }
+}
diff --git a/Service.php b/Service.php
new file mode 100644
index 0000000..048d45d
--- /dev/null
+++ b/Service.php
@@ -0,0 +1,402 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use Box\Mod\Support\Entity\Helpdesk;
+use Box\Mod\Support\Entity\SupportTicket;
+use FOSSBilling\InformationException;
+use FOSSBilling\Tools;
+use Pimple\Container;
+
+class Service implements \FOSSBilling\InjectionAwareInterface
+{
+    protected ?Container $di = null;
+
+    public function setDi(Container $di): void
+    {
+        $this->di = $di;
+    }
+
+    public function getDi(): ?Container
+    {
+        return $this->di;
+    }
+
+    public function getModulePermissions(): array
+    {
+        return ['manage_settings' => [
+            'type' => 'bool', 'display_name' => 'Manage Mail Gateway settings',
+            'description' => 'Configure the inbound mailbox and ticket routing.',
+        ]];
+    }
+
+    public function getSettings(): array
+    {
+        return $this->settingsStore()->getPublic();
+    }
+
+    public function getMailboxes(): array
+    {
+        return $this->settingsStore()->getAllPublic();
+    }
+
+    public function getDependencyStatus(): array
+    {
+        return ($this->di['mailgateway_dependency_installer'] ?? new DependencyInstaller())->status();
+    }
+
+    public function installDependencies(bool $force = false): array
+    {
+        // Share the poller's lock so imports cannot run while vendor is being written.
+        if ((int) $this->di['dbal']->fetchOne('SELECT GET_LOCK(?, 0)', ['fossbilling_mailgateway_poll']) !== 1) {
+            throw new InformationException('Mail Gateway is busy. Try installing dependencies again after polling finishes.');
+        }
+        try {
+            return ($this->di['mailgateway_dependency_installer'] ?? new DependencyInstaller())->install($force);
+        } finally {
+            $this->di['dbal']->fetchOne('SELECT RELEASE_LOCK(?)', ['fossbilling_mailgateway_poll']);
+        }
+    }
+
+    public function testConnection(array $data): array
+    {
+        $id = $data['mailbox_id'] ?? 'default';
+        if (!is_string($id)) {
+            throw new \FOSSBilling\InformationException('Mailbox not found');
+        }
+        $store = $this->settingsStore();
+        $settings = $store->get($id);
+        $result = ($this->di['mailgateway_connection_test'] ?? new ImapConnectionTest())->test($settings, true);
+        $store->recordTest($id, $settings, $result);
+        return $result;
+    }
+
+    public function saveSettings(array $data): bool
+    {
+        if (in_array($data['enabled'] ?? false, [true, 1, '1'], true)) {
+            $status = $this->configureNotifications();
+            if (!$status['ready']) {
+                throw new InformationException(implode(' ', $status['errors']));
+            }
+        }
+        return $this->settingsStore()->save($data);
+    }
+
+    public function getNotificationStatus(): array
+    {
+        return (new NotificationSettings($this->di))->status();
+    }
+
+    public function configureNotifications(): array
+    {
+        return (new NotificationSettings($this->di))->repair();
+    }
+
+    public function deleteMailbox(array $data): bool
+    {
+        $id = $data['mailbox_id'] ?? null;
+        if (!is_string($id) || $id === '') {
+            throw new InformationException('Mailbox ID is required');
+        }
+        // Prevent a removed mailbox from being imported by an already-running poll.
+        if ((int) $this->di['dbal']->fetchOne('SELECT GET_LOCK(?, 0)', ['fossbilling_mailgateway_poll']) !== 1) {
+            throw new InformationException('Mail Gateway is busy. Try deleting the mailbox after polling finishes.');
+        }
+        try {
+            return $this->settingsStore()->delete($id);
+        } finally {
+            $this->di['dbal']->fetchOne('SELECT RELEASE_LOCK(?)', ['fossbilling_mailgateway_poll']);
+        }
+    }
+
+    private function settingsStore(): object
+    {
+        return $this->di['mailgateway_settings'] ?? new Settings($this->di);
+    }
+
+    public function poll(bool $force = false): array
+    {
+        return (new Poller($this->di, $this))->poll($force);
+    }
+
+    public static function onBeforeAdminCronRun(\Box_Event $event): void
+    {
+        $di = $event->getDi();
+        try {
+            $result = $di['mod_service']('mailgateway')->poll();
+            if ($result['status'] === 'completed') {
+                $di['logger']->info('Mail Gateway polling: ' . json_encode($result, JSON_THROW_ON_ERROR));
+            }
+        } catch (\Throwable) {
+            // A mail gateway outage must not interrupt billing or the outgoing queue.
+            $di['logger']->warning('Mail Gateway polling unavailable; FOSSBilling cron will continue');
+        }
+    }
+
+    private function setupTables(): void
+    {
+        foreach (explode(';', file_get_contents(__DIR__ . '/schema.sql')) as $statement) {
+            if (trim($statement) !== '') {
+                $this->di['dbal']->executeStatement($statement);
+            }
+        }
+    }
+
+    private function setupTemplates(): void
+    {
+        ($this->di['mailgateway_template_installer'] ?? new TemplateInstaller($this->di))->install();
+    }
+
+    public function setup(): bool
+    {
+        if ((int) $this->di['dbal']->fetchOne('SELECT GET_LOCK(?, 0)', ['fossbilling_mailgateway_poll']) !== 1) {
+            throw new InformationException('Mail Gateway is busy. Try setup again after polling finishes.');
+        }
+        try {
+            $this->setupTables();
+            $this->setupTemplates();
+            return true;
+        } finally {
+            $this->di['dbal']->fetchOne('SELECT RELEASE_LOCK(?)', ['fossbilling_mailgateway_poll']);
+        }
+    }
+
+    public function install(): bool
+    {
+        $this->setupTables();
+        $this->setupTemplates();
+
+        try {
+            $this->installDependencies();
+        } catch (\Throwable) {
+            // Keep the settings page reachable if the host cannot install Composer packages.
+            // Dependency status there provides the install button or SSH instructions.
+            $this->di['logger']->warning('Mail Gateway tables are ready, but dependencies could not be installed automatically. Open Mail Gateway settings to finish installation.');
+        }
+
+        return true;
+    }
+
+    /** Create a customer or guest ticket from a decoded inbound message. */
+    public function import(array $data): array
+    {
+        $policy = new InboundPolicy();
+        $reason = $policy->ignoreReason($policy->headers($data));
+        if ($reason !== null) {
+            return ['action' => 'ignored', 'reason' => $reason];
+        }
+        $sender = $this->senderEmail($data);
+
+        $subject = $this->requiredString($data, 'subject');
+        if (!mb_check_encoding($subject, 'UTF-8') || mb_strlen($subject, 'UTF-8') > 255
+            || preg_match('/[\x00-\x1F\x7F]/', $subject)) {
+            throw new InformationException('Subject must be valid UTF-8, at most 255 characters, with no control characters');
+        }
+
+        $content = $this->messageContent($data);
+
+        $senderName = isset($data['sender_name']) ? $this->requiredString($data, 'sender_name') : $sender;
+        if (!mb_check_encoding($senderName, 'UTF-8') || mb_strlen($senderName, 'UTF-8') > 255
+            || preg_match('/[\x00-\x1F\x7F]/', $senderName)) {
+            throw new InformationException('Sender name must be valid UTF-8, at most 255 characters, with no control characters');
+        }
+
+        // Exact mailbox matching, case-insensitive; never use LIKE or choose the first match.
+        $clients = $this->di['dbal']->fetchFirstColumn(
+            'SELECT id FROM client WHERE LOWER(email) = LOWER(:email) LIMIT 2',
+            ['email' => $sender],
+        );
+        if (count($clients) > 1) {
+            throw new InformationException('Multiple customers match sender_email');
+        }
+
+        $support = $this->di['mod_service']('support');
+        $store = $this->settingsStore();
+        $settings = isset($data['mailbox']) && $store instanceof Settings
+            ? $store->forAddress($data['mailbox']) : $store->get();
+        $helpdeskId = $settings['support_helpdesk_id'];
+        $helpdesks = $helpdeskId !== null
+            ? [$support->getHelpdeskRepository()->find((int) $helpdeskId)]
+            : $support->getHelpdeskRepository()->findBy(['name' => 'General'], null, 2);
+        if (count($helpdesks) !== 1 || !$helpdesks[0] instanceof Helpdesk) {
+            throw new InformationException('Choose an existing helpdesk in Mail Gateway settings, or configure exactly one General helpdesk');
+        }
+
+        if ($clients === []) {
+            // Guest creation sends its own acknowledgement without a client
+            // session. Keep its access hash private; return only the ticket ID.
+            $hash = $this->withNotificationCooldown($sender, fn () => $support->ticketCreateForGuest([
+                'name' => $senderName,
+                'email' => $sender,
+                'subject' => $subject,
+                'content' => $content,
+                'support_helpdesk_id' => $helpdesks[0]->getId(),
+            ]));
+            $ticket = $support->findOneByHash($hash);
+
+            return ['ticket_id' => $ticket->getId(), 'client_id' => null, 'support_helpdesk_id' => $helpdesks[0]->getId()];
+        }
+
+        $client = $this->di['db']->getExistingModelById('Client', (int) $clients[0]);
+        if (!$client instanceof \Model_Client) {
+            throw new InformationException('Customer identity could not be loaded');
+        }
+
+        $id = $this->withNotificationCooldown($sender, fn () => $support->ticketCreateForClient($client, $helpdesks[0], [
+            'subject' => $subject,
+            'content' => $content,
+        ]));
+
+        // A canned acknowledgement counts as an admin reply in Support and
+        // puts the ticket on hold. Incoming mail still needs staff attention.
+        $ticket = $support->getTicketById($id);
+        if ($ticket->getStatus() === SupportTicket::STATUS_ONHOLD) {
+            $ticket->setStatus(SupportTicket::STATUS_OPEN);
+            $this->di['em']->flush();
+        }
+
+        // Support's normal notification hook requires a customer session.
+        // Cron imports have no customer session.
+        if (!$this->di['auth']->isClientLoggedIn()) {
+            $this->queueAutomaticTemplate($sender, [
+                'to_client' => (int) $client->id,
+                'code' => 'mod_support_ticket_open',
+                'ticket' => $support->toApiArray($ticket, true, $client),
+            ]);
+        }
+
+        return ['ticket_id' => $id, 'client_id' => (int) $client->id, 'support_helpdesk_id' => $helpdesks[0]->getId()];
+    }
+
+    /** Reply to an explicitly identified ticket; never infer ownership from a subject. */
+    public function reply(array $data): array
+    {
+        $policy = new InboundPolicy();
+        $reason = $policy->ignoreReason($policy->headers($data));
+        if ($reason !== null) {
+            return ['action' => 'ignored', 'reason' => $reason];
+        }
+        $sender = $this->senderEmail($data);
+        $content = $this->messageContent($data);
+        $rawId = $data['ticket_id'] ?? null;
+        if ((!is_int($rawId) && !is_string($rawId))
+            || filter_var($rawId, FILTER_VALIDATE_INT, ['options' => ['min_range' => 1]]) === false) {
+            throw new InformationException('A positive integer ticket_id is required');
+        }
+
+        $support = $this->di['mod_service']('support');
+        $ticket = $support->getTicketById((int) $rawId);
+        if ($ticket->isGuestTicket()) {
+            if (strcasecmp($sender, (string) $ticket->getAuthorEmail()) !== 0) {
+                throw new InformationException('Sender does not own this ticket');
+            }
+            $identity = new \FOSSBilling\Identity\Guest();
+        } else {
+            $ids = $this->di['dbal']->fetchFirstColumn(
+                'SELECT id FROM client WHERE LOWER(email) = LOWER(:email) LIMIT 2',
+                ['email' => $sender],
+            );
+            if (count($ids) !== 1 || (int) $ids[0] !== $ticket->getClientId()) {
+                throw new InformationException('Sender does not uniquely match the ticket owner');
+            }
+            $identity = $this->di['db']->getExistingModelById('Client', (int) $ids[0]);
+            if (!$identity instanceof \Model_Client) {
+                throw new InformationException('Customer identity could not be loaded');
+            }
+        }
+
+        if (!$support->canBeReopened($ticket)) {
+            throw new InformationException('Ticket cannot be reopened');
+        }
+
+        $messageId = $support->ticketReply($ticket, $identity, $content);
+
+        return ['ticket_id' => $ticket->getId(), 'message_id' => $messageId];
+    }
+
+    public function notifySenderMismatch(string $sender, int $ticketId): void
+    {
+        try {
+            $this->queueAutomaticTemplate($sender, [
+                'to' => $sender,
+                'code' => 'mailgateway_sender_mismatch',
+                'sender_email' => $sender,
+                // Only echo the reference supplied by the sender; do not pass
+                // the ticket's details, owner identity, or guest access hash.
+                'ticket_id' => $ticketId,
+            ]);
+        } catch (\Exception) {
+            // Notification failure must never permit the rejected reply.
+            $this->di['logger']->warning('Mail Gateway could not queue the sender mismatch notification');
+        }
+    }
+
+    private function senderEmail(array $data): string
+    {
+        $sender = $this->requiredString($data, 'sender_email');
+        if (strlen($sender) > 255 || !filter_var($sender, FILTER_VALIDATE_EMAIL)) {
+            throw new InformationException('A valid sender_email is required');
+        }
+
+        return $sender;
+    }
+
+    private function queueAutomaticTemplate(string $sender, array $data): bool
+    {
+        // An injectable limiter permits isolated tests without a live database.
+        $limiter = $this->di['mailgateway_notification_cooldown'] ?? new NotificationCooldown($this->di['dbal']);
+        return $limiter->run($sender, fn () => $this->di['mod_service']('email')->sendTemplate($data));
+    }
+
+    private function withNotificationCooldown(string $sender, callable $create): mixed
+    {
+        $lookup = $this->di['mod_service'];
+        $proxy = null;
+        unset($this->di['mod_service']);
+        $this->di['mod_service'] = $this->di->protect(function ($module, $sub = '') use ($lookup, $sender, &$proxy) {
+            if (strtolower($module) !== 'email' || $sub !== '') {
+                return $lookup($module, $sub);
+            }
+            if ($proxy === null) {
+                $email = $lookup($module, $sub);
+                $proxy = new NotificationEmailProxy($email, function ($data) use ($sender, $email) {
+                    $limiter = $this->di['mailgateway_notification_cooldown'] ?? new NotificationCooldown($this->di['dbal']);
+                    return $limiter->run($sender, fn () => $email->sendTemplate($data));
+                });
+            }
+            return $proxy;
+        });
+        try {
+            return $create();
+        } finally {
+            unset($this->di['mod_service']);
+            $this->di['mod_service'] = $this->di->protect($lookup);
+        }
+    }
+
+    private function messageContent(array $data): string
+    {
+        $content = $this->requiredString($data, 'content');
+        // Support stores this in a TEXT column (maximum 65,535 bytes).
+        if (!mb_check_encoding($content, 'UTF-8') || strlen($content) > RuntimeConfig::get('max_ticket_body_bytes')) {
+            throw new InformationException('Content must be valid UTF-8 and within the configured ticket body limit');
+        }
+        $content = Tools::sanitizeMarkdownContent($content);
+        if ($content === '') {
+            throw new InformationException('Content must not be empty');
+        }
+
+        return $content;
+    }
+
+    private function requiredString(array $data, string $key): string
+    {
+        if (!isset($data[$key]) || !is_string($data[$key]) || trim($data[$key]) === '') {
+            throw new InformationException($key . ' must be a non-empty string');
+        }
+
+        return trim($data[$key]);
+    }
+}
diff --git a/Settings.php b/Settings.php
new file mode 100644
index 0000000..060f17f
--- /dev/null
+++ b/Settings.php
@@ -0,0 +1,267 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use Box\Mod\Support\Entity\Helpdesk;
+use Doctrine\DBAL\Exception\UniqueConstraintViolationException;
+use FOSSBilling\InformationException;
+use Pimple\Container;
+
+class Settings
+{
+    public const DEFAULTS = [
+        'enabled' => false, 'host' => '', 'port' => 993,
+        'encryption' => 'ssl', 'validate_cert' => true,
+        'username' => '', 'password' => '',
+        'mailbox' => '', 'inbox_folder' => 'INBOX',
+        'processed_folder' => 'Processed', 'ignored_folder' => 'Ignored',
+        'failed_folder' => 'Failed', 'support_helpdesk_id' => null,
+        'tested_config_hash' => null, 'test_result' => null,
+    ];
+
+    public function __construct(private Container $di) {}
+
+    private function all(): array
+    {
+        try {
+            $encrypted = $this->di['dbal']->fetchOne('SELECT config_encrypted FROM mailgateway_settings WHERE id = 1');
+        } catch (\Doctrine\DBAL\Exception\TableNotFoundException) {
+            // Keep Advanced setup reachable if the module tables need creating.
+            return ['default' => self::DEFAULTS];
+        }
+        if ($encrypted === false) {
+            return ['default' => self::DEFAULTS];
+        }
+        $plain = $this->di['crypt']->decrypt($encrypted);
+        if (!is_string($plain)) {
+            throw new InformationException('Mail Gateway settings could not be decrypted');
+        }
+        $decoded = json_decode($plain, true, 512, JSON_THROW_ON_ERROR);
+        $mailboxes = $decoded['mailboxes'] ?? ['default' => $decoded];
+        return array_map(function ($settings) {
+            // Older configurations stored this unused operational value per mailbox.
+            unset($settings['poll_interval_minutes']);
+            $settings = array_replace(self::DEFAULTS, $settings);
+            if (!$this->verified($settings)) {
+                $settings['enabled'] = false;
+            }
+            return $settings;
+        }, $mailboxes);
+    }
+
+    /** Internal polling configuration, including encrypted-at-rest credentials. */
+    public function getAll(): array
+    {
+        return $this->all();
+    }
+
+    public function get(?string $id = null): array
+    {
+        $mailboxes = $this->all();
+        if ($id === null) {
+            return $mailboxes['default'] ?? (reset($mailboxes) ?: self::DEFAULTS);
+        }
+        return $mailboxes[$id] ?? throw new InformationException('Mailbox not found');
+    }
+
+    public function getAllPublic(): array
+    {
+        return array_map(fn ($settings) => $this->publicSettings($settings), $this->all());
+    }
+
+    public function delete(string $id): bool
+    {
+        return $this->di['dbal']->transactional(function ($connection) use ($id): bool {
+            if ($connection->getDatabasePlatform() instanceof \Doctrine\DBAL\Platforms\AbstractMySQLPlatform) {
+                $connection->fetchOne('SELECT id FROM mailgateway_settings WHERE id = 1 FOR UPDATE');
+            }
+            $mailboxes = $this->all();
+            if (!isset($mailboxes[$id])) {
+                throw new InformationException('Mailbox not found');
+            }
+            unset($mailboxes[$id]);
+            $encrypted = $this->di['crypt']->encrypt(json_encode(['mailboxes' => $mailboxes], JSON_THROW_ON_ERROR));
+            $connection->update('mailgateway_settings', ['config_encrypted' => $encrypted], ['id' => 1]);
+            return true;
+        });
+    }
+
+    private function publicSettings(array $settings): array
+    {
+        $settings['password_configured'] = $settings['password'] !== '';
+        $settings['test_passed'] = $this->verified($settings);
+        unset($settings['password'], $settings['tested_config_hash']);
+        return $settings;
+    }
+
+    private function fingerprint(array $settings): string
+    {
+        $connection = array_intersect_key($settings, array_flip(['host', 'port', 'encryption', 'username',
+            'password', 'mailbox', 'inbox_folder', 'processed_folder', 'ignored_folder', 'failed_folder']));
+        ksort($connection);
+        return hash('sha256', json_encode($connection, JSON_THROW_ON_ERROR));
+    }
+
+    private function verified(array $settings): bool
+    {
+        return is_string($settings['tested_config_hash'])
+            && hash_equals($settings['tested_config_hash'], $this->fingerprint($settings));
+    }
+
+    public function recordTest(string $id, array $testedSettings, array $result): bool
+    {
+        return $this->di['dbal']->transactional(function ($connection) use ($id, $testedSettings, $result): bool {
+            if ($connection->getDatabasePlatform() instanceof \Doctrine\DBAL\Platforms\AbstractMySQLPlatform) {
+                $connection->fetchOne('SELECT id FROM mailgateway_settings WHERE id = 1 FOR UPDATE');
+            }
+            $mailboxes = $this->all();
+            if (!isset($mailboxes[$id]) || $this->fingerprint($mailboxes[$id]) !== $this->fingerprint($testedSettings)) {
+                throw new InformationException('Mailbox settings changed during the test. Save and test again.');
+            }
+            $mailboxes[$id]['tested_config_hash'] = $result['success'] ? $this->fingerprint($testedSettings) : null;
+            $mailboxes[$id]['test_result'] = $result;
+            if (!$result['success']) {
+                $mailboxes[$id]['enabled'] = false;
+            }
+            $encrypted = $this->di['crypt']->encrypt(json_encode(['mailboxes' => $mailboxes], JSON_THROW_ON_ERROR));
+            $connection->update('mailgateway_settings', ['config_encrypted' => $encrypted], ['id' => 1]);
+            return true;
+        });
+    }
+
+    public function forAddress(string $address): array
+    {
+        foreach ($this->all() as $settings) {
+            if (strcasecmp($settings['mailbox'], $address) === 0) {
+                return $settings;
+            }
+        }
+        throw new InformationException('Receiving mailbox is not configured');
+    }
+
+    public function getPublic(): array
+    {
+        return $this->publicSettings($this->get());
+    }
+
+    public function save(array $data): bool
+    {
+        return $this->di['dbal']->transactional(function ($connection) use ($data): bool {
+            // Lock before reading so concurrent saves cannot overwrite another mailbox.
+            if ($connection->getDatabasePlatform() instanceof \Doctrine\DBAL\Platforms\AbstractMySQLPlatform) {
+                $connection->fetchOne('SELECT id FROM mailgateway_settings WHERE id = 1 FOR UPDATE');
+            }
+            return $this->saveMailbox($data);
+        });
+    }
+
+    private function saveMailbox(array $data): bool
+    {
+        $mailboxes = $this->all();
+        $id = $data['mailbox_id'] ?? 'default';
+        if (!is_string($id) || ($id !== 'new' && !isset($mailboxes[$id]))) {
+            throw new InformationException('Mailbox not found');
+        }
+        $old = $id === 'new' ? self::DEFAULTS : $mailboxes[$id];
+        $settings = self::DEFAULTS;
+        $settings['enabled'] = $this->boolean($data['enabled'] ?? false);
+        if ($settings['enabled'] && !($this->di['mailgateway_dependency_installer'] ?? new DependencyInstaller())->status()['installed']) {
+            throw new InformationException('Install Mail Gateway dependencies before enabling mailbox importing');
+        }
+        foreach (['host', 'username', 'mailbox', 'inbox_folder', 'processed_folder', 'ignored_folder', 'failed_folder'] as $field) {
+            if (!isset($data[$field]) || !is_string($data[$field])) {
+                throw new InformationException($field . ' is required');
+            }
+            $value = trim($data[$field]);
+            if ($value === '' || mb_strlen($value, 'UTF-8') > 255 || !mb_check_encoding($value, 'UTF-8')
+                || preg_match('/[\x00-\x1F\x7F]/', $value)) {
+                throw new InformationException($field . ' must be a non-empty value of at most 255 characters, without control characters');
+            }
+            $settings[$field] = $value;
+        }
+        if (!filter_var($settings['host'], FILTER_VALIDATE_IP)
+            && !filter_var($settings['host'], FILTER_VALIDATE_DOMAIN, FILTER_FLAG_HOSTNAME)) {
+            throw new InformationException('IMAP host must be a hostname or IP address');
+        }
+        if (!filter_var($settings['mailbox'], FILTER_VALIDATE_EMAIL) || strlen($settings['mailbox']) > 255) {
+            throw new InformationException('A valid mailbox email address is required');
+        }
+        $settings['mailbox'] = strtolower($settings['mailbox']);
+        $settings['port'] = $this->integer($data['port'] ?? null, 1, 65535, 'port');
+        $settings['encryption'] = $data['encryption'] ?? null;
+        if (!in_array($settings['encryption'], ['ssl', 'tls'], true)) {
+            throw new InformationException('Choose implicit TLS or STARTTLS');
+        }
+        $folders = array_map(fn ($key) => mb_strtolower($settings[$key], 'UTF-8'),
+            ['inbox_folder', 'processed_folder', 'ignored_folder', 'failed_folder']);
+        if (count(array_unique($folders)) !== 4) {
+            throw new InformationException('Inbox, processed, ignored, and failed folders must be different');
+        }
+        $settings['support_helpdesk_id'] = $this->integer($data['support_helpdesk_id'] ?? null, 1, PHP_INT_MAX, 'support_helpdesk_id');
+        if (!$this->di['mod_service']('support')->getHelpdeskRepository()->find($settings['support_helpdesk_id']) instanceof Helpdesk) {
+            throw new InformationException('Choose an existing helpdesk');
+        }
+        $password = $data['password'] ?? '';
+        if (!is_string($password) || strlen($password) > 4096 || str_contains($password, "\0")) {
+            throw new InformationException('Invalid mailbox password');
+        }
+        $clear = $this->boolean($data['clear_password'] ?? false);
+        if ($clear && $password !== '') {
+            throw new InformationException('Choose either a new password or clear the saved password');
+        }
+        $settings['password'] = $clear ? '' : ($password !== '' ? $password : $old['password']);
+        if ($settings['enabled'] && $settings['password'] === '') {
+            throw new InformationException('Save a mailbox password before enabling imports');
+        }
+        $changed = $this->fingerprint($settings) !== $this->fingerprint($old);
+        $settings['tested_config_hash'] = $changed ? null : $old['tested_config_hash'];
+        $settings['test_result'] = $changed ? null : $old['test_result'];
+        if ($settings['enabled'] && !$this->verified($settings)) {
+            if ($changed && $this->verified($old)) {
+                // Saving changed connection details disables imports until retested.
+                $settings['enabled'] = false;
+            } else {
+                throw new InformationException('Save this mailbox and successfully run Test Connection and Create Folders before enabling importing');
+            }
+        }
+        foreach ($mailboxes as $otherId => $other) {
+            if ($otherId !== $id && strcasecmp($other['mailbox'], $settings['mailbox']) === 0) {
+                throw new InformationException('This mailbox email address is already configured');
+            }
+        }
+        if ($id === 'new') {
+            $id = bin2hex(random_bytes(16));
+        }
+        $mailboxes[$id] = $settings;
+        $encrypted = $this->di['crypt']->encrypt(json_encode(['mailboxes' => $mailboxes], JSON_THROW_ON_ERROR));
+        $this->di['dbal']->transactional(function ($connection) use ($encrypted): void {
+            // MySQL serializes concurrent settings saves on this singleton row.
+            try {
+                $connection->insert('mailgateway_settings', ['id' => 1, 'config_encrypted' => $encrypted]);
+            } catch (UniqueConstraintViolationException) {
+                // Existing singleton configuration; update under its row lock.
+            }
+            $connection->update('mailgateway_settings', ['config_encrypted' => $encrypted], ['id' => 1]);
+        });
+        return true;
+    }
+
+    private function integer(mixed $value, int $min, int $max, string $field): int
+    {
+        if ((!is_string($value) && !is_int($value))
+            || filter_var($value, FILTER_VALIDATE_INT, ['options' => ['min_range' => $min, 'max_range' => $max]]) === false) {
+            throw new InformationException($field . ' is invalid');
+        }
+        return (int) $value;
+    }
+
+    private function boolean(mixed $value): bool
+    {
+        if (!in_array($value, [true, false, 0, 1, '0', '1'], true)) {
+            throw new InformationException('Invalid checkbox value');
+        }
+        return in_array($value, [true, 1, '1'], true);
+    }
+}
diff --git a/TemplateInstaller.php b/TemplateInstaller.php
new file mode 100644
index 0000000..7aa9036
--- /dev/null
+++ b/TemplateInstaller.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Box\Mod\Mailgateway;
+
+use Pimple\Container;
+
+class TemplateInstaller
+{
+    public function __construct(private Container $di) {}
+
+    public function install(): void
+    {
+        $code = 'mailgateway_sender_mismatch';
+        $email = $this->di['mod_service']('email');
+        // Preserve existing custom content and enabled/disabled preference.
+        if ($email->getTemplateRepository()->findOneByActionCode($code) !== null) {
+            return;
+        }
+        $source = file_get_contents(__DIR__ . '/templates/email/' . $code . '.html.twig');
+        if (!is_string($source)
+            || !preg_match('/{%\s*block subject\s*%}(.*?){%\s*endblock\s*%}/s', $source, $subject)
+            || !preg_match('/{%\s*block content\s*%}(.*?){%\s*endblock\s*%}/s', $source, $content)) {
+            throw new \RuntimeException('Mail Gateway sender-mismatch template is missing or invalid');
+        }
+        // This existing custom action code does not use the mod_* discovery convention.
+        $email->templateCreate($code, trim($subject[1]), trim($content[1]), 1, 'mailgateway');
+    }
+}
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..8d56034
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,5 @@
+{
+    "require": {
+        "webklex/php-imap": "^6.2"
+    }
+}
diff --git a/composer.lock b/composer.lock
new file mode 100644
index 0000000..298a59e
--- /dev/null
+++ b/composer.lock
@@ -0,0 +1,1704 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "5cc550c87df98ff88db99d5cbe524f1c",
+    "packages": [
+        {
+            "name": "carbonphp/carbon-doctrine-types",
+            "version": "3.2.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/CarbonPHP/carbon-doctrine-types.git",
+                "reference": "5fa5eacafd9ef47c8c6ab9143fc901ba0194d3dc"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/CarbonPHP/carbon-doctrine-types/zipball/5fa5eacafd9ef47c8c6ab9143fc901ba0194d3dc",
+                "reference": "5fa5eacafd9ef47c8c6ab9143fc901ba0194d3dc",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^8.1"
+            },
+            "conflict": {
+                "doctrine/dbal": "<4.0.0 || >=5.0.0"
+            },
+            "require-dev": {
+                "doctrine/dbal": "^4.0.0",
+                "nesbot/carbon": "^2.71.0 || ^3.0.0",
+                "phpunit/phpunit": "^10.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "3.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Carbon\\Doctrine\\": "src/Carbon/Doctrine/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "KyleKatarn",
+                    "email": "kylekatarnls@gmail.com"
+                }
+            ],
+            "description": "Types to use Carbon in Doctrine",
+            "keywords": [
+                "carbon",
+                "date",
+                "datetime",
+                "doctrine",
+                "time"
+            ],
+            "support": {
+                "issues": "https://github.com/CarbonPHP/carbon-doctrine-types/issues",
+                "source": "https://github.com/CarbonPHP/carbon-doctrine-types/tree/3.2.1"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/kylekatarnls",
+                    "type": "github"
+                },
+                {
+                    "url": "https://opencollective.com/Carbon",
+                    "type": "open_collective"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/nesbot/carbon",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-09-06T14:11:38+00:00"
+        },
+        {
+            "name": "doctrine/inflector",
+            "version": "2.1.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/doctrine/inflector.git",
+                "reference": "6d6c96277ea252fc1304627204c3d5e6e15faa3b"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/doctrine/inflector/zipball/6d6c96277ea252fc1304627204c3d5e6e15faa3b",
+                "reference": "6d6c96277ea252fc1304627204c3d5e6e15faa3b",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.2 || ^8.0"
+            },
+            "require-dev": {
+                "doctrine/coding-standard": "^12.0 || ^13.0",
+                "phpstan/phpstan": "^1.12 || ^2.0",
+                "phpstan/phpstan-phpunit": "^1.4 || ^2.0",
+                "phpstan/phpstan-strict-rules": "^1.6 || ^2.0",
+                "phpunit/phpunit": "^8.5 || ^12.2"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Doctrine\\Inflector\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Guilherme Blanco",
+                    "email": "guilhermeblanco@gmail.com"
+                },
+                {
+                    "name": "Roman Borschel",
+                    "email": "roman@code-factory.org"
+                },
+                {
+                    "name": "Benjamin Eberlei",
+                    "email": "kontakt@beberlei.de"
+                },
+                {
+                    "name": "Jonathan Wage",
+                    "email": "jonwage@gmail.com"
+                },
+                {
+                    "name": "Johannes Schmitt",
+                    "email": "schmittjoh@gmail.com"
+                }
+            ],
+            "description": "PHP Doctrine Inflector is a small library that can perform string manipulations with regard to upper/lowercase and singular/plural forms of words.",
+            "homepage": "https://www.doctrine-project.org/projects/inflector.html",
+            "keywords": [
+                "inflection",
+                "inflector",
+                "lowercase",
+                "manipulation",
+                "php",
+                "plural",
+                "singular",
+                "strings",
+                "uppercase",
+                "words"
+            ],
+            "support": {
+                "issues": "https://github.com/doctrine/inflector/issues",
+                "source": "https://github.com/doctrine/inflector/tree/2.1.0"
+            },
+            "funding": [
+                {
+                    "url": "https://www.doctrine-project.org/sponsorship.html",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://www.patreon.com/phpdoctrine",
+                    "type": "patreon"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/doctrine%2Finflector",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2025-08-10T19:31:58+00:00"
+        },
+        {
+            "name": "illuminate/collections",
+            "version": "v13.35.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/collections.git",
+                "reference": "6eebd20c5ec8958a782008aea1374e9600cf8135"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/collections/zipball/6eebd20c5ec8958a782008aea1374e9600cf8135",
+                "reference": "6eebd20c5ec8958a782008aea1374e9600cf8135",
+                "shasum": ""
+            },
+            "require": {
+                "illuminate/conditionable": "^13.0",
+                "illuminate/contracts": "^13.0",
+                "illuminate/macroable": "^13.0",
+                "php": "^8.3",
+                "symfony/polyfill-php84": "^1.36",
+                "symfony/polyfill-php85": "^1.36",
+                "symfony/polyfill-php86": "^1.36"
+            },
+            "suggest": {
+                "illuminate/http": "Required to convert collections to API resources (^13.0).",
+                "symfony/var-dumper": "Required to use the dump method (^7.4 || ^8.0)."
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "13.0.x-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "functions.php",
+                    "helpers.php"
+                ],
+                "psr-4": {
+                    "Illuminate\\Support\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Collections package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2026-10-02T12:50:49+00:00"
+        },
+        {
+            "name": "illuminate/conditionable",
+            "version": "v13.35.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/conditionable.git",
+                "reference": "7f1ef52d9a346f829421b296adfb7644a951b216"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/conditionable/zipball/7f1ef52d9a346f829421b296adfb7644a951b216",
+                "reference": "7f1ef52d9a346f829421b296adfb7644a951b216",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^8.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "13.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Illuminate\\Support\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Conditionable package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2026-02-25T16:07:55+00:00"
+        },
+        {
+            "name": "illuminate/contracts",
+            "version": "v13.35.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/contracts.git",
+                "reference": "0cabe75392aad93ac739bbb220a3f5d943b12b30"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/contracts/zipball/0cabe75392aad93ac739bbb220a3f5d943b12b30",
+                "reference": "0cabe75392aad93ac739bbb220a3f5d943b12b30",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^8.3",
+                "psr/container": "^1.1.1 || ^2.0.1",
+                "psr/simple-cache": "^1.0 || ^2.0 || ^3.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "13.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Illuminate\\Contracts\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Contracts package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2026-09-25T12:59:28+00:00"
+        },
+        {
+            "name": "illuminate/macroable",
+            "version": "v13.35.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/macroable.git",
+                "reference": "59b5b5f3cf290a91db8cf6cd3d35ff56978bc057"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/macroable/zipball/59b5b5f3cf290a91db8cf6cd3d35ff56978bc057",
+                "reference": "59b5b5f3cf290a91db8cf6cd3d35ff56978bc057",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^8.2"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "13.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Illuminate\\Support\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Macroable package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2026-04-29T09:35:06+00:00"
+        },
+        {
+            "name": "illuminate/pagination",
+            "version": "v13.35.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/pagination.git",
+                "reference": "0847cb3408d2ac92b96793e6e308a90973cb7fd2"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/pagination/zipball/0847cb3408d2ac92b96793e6e308a90973cb7fd2",
+                "reference": "0847cb3408d2ac92b96793e6e308a90973cb7fd2",
+                "shasum": ""
+            },
+            "require": {
+                "ext-filter": "*",
+                "illuminate/collections": "^13.0",
+                "illuminate/contracts": "^13.0",
+                "illuminate/support": "^13.0",
+                "php": "^8.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "13.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Illuminate\\Pagination\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Pagination package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2026-08-02T20:48:08+00:00"
+        },
+        {
+            "name": "illuminate/reflection",
+            "version": "v13.35.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/reflection.git",
+                "reference": "2b6ba33970dd84849322a6a9857647ca96c1bb66"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/reflection/zipball/2b6ba33970dd84849322a6a9857647ca96c1bb66",
+                "reference": "2b6ba33970dd84849322a6a9857647ca96c1bb66",
+                "shasum": ""
+            },
+            "require": {
+                "illuminate/collections": "^13.0",
+                "illuminate/contracts": "^13.0",
+                "php": "^8.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "13.0.x-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "helpers.php"
+                ],
+                "psr-4": {
+                    "Illuminate\\Support\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Reflection package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2026-08-03T17:56:24+00:00"
+        },
+        {
+            "name": "illuminate/support",
+            "version": "v13.35.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/illuminate/support.git",
+                "reference": "ca230c018111767a6dd7cab7b157ef346801454a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/illuminate/support/zipball/ca230c018111767a6dd7cab7b157ef346801454a",
+                "reference": "ca230c018111767a6dd7cab7b157ef346801454a",
+                "shasum": ""
+            },
+            "require": {
+                "doctrine/inflector": "^2.0",
+                "ext-ctype": "*",
+                "ext-filter": "*",
+                "ext-mbstring": "*",
+                "illuminate/collections": "^13.0",
+                "illuminate/conditionable": "^13.0",
+                "illuminate/contracts": "^13.0",
+                "illuminate/macroable": "^13.0",
+                "illuminate/reflection": "^13.0",
+                "nesbot/carbon": "^3.8.4",
+                "php": "^8.3",
+                "symfony/polyfill-php85": "^1.36",
+                "voku/portable-ascii": "^2.0.2"
+            },
+            "conflict": {
+                "tightenco/collect": "<5.5.33"
+            },
+            "replace": {
+                "spatie/once": "*"
+            },
+            "suggest": {
+                "illuminate/filesystem": "Required to use the Composer class (^13.0).",
+                "laravel/serializable-closure": "Required to use the once function (^2.0.10).",
+                "league/commonmark": "Required to use Str::markdown() and Stringable::markdown() (^2.7).",
+                "league/uri": "Required to use the Uri class (^7.5.1).",
+                "ramsey/uuid": "Required to use Str::uuid() (^4.7).",
+                "symfony/process": "Required to use the Composer class (^7.4 || ^8.0).",
+                "symfony/uid": "Required to use Str::ulid() (^7.4 || ^8.0).",
+                "symfony/var-dumper": "Required to use the dd function (^7.4 || ^8.0).",
+                "vlucas/phpdotenv": "Required to use the Env class and env helper (^5.6.1)."
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "13.0.x-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "functions.php",
+                    "helpers.php"
+                ],
+                "psr-4": {
+                    "Illuminate\\Support\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Taylor Otwell",
+                    "email": "taylor@laravel.com"
+                }
+            ],
+            "description": "The Illuminate Support package.",
+            "homepage": "https://laravel.com",
+            "support": {
+                "issues": "https://github.com/laravel/framework/issues",
+                "source": "https://github.com/laravel/framework"
+            },
+            "time": "2026-10-05T15:51:39+00:00"
+        },
+        {
+            "name": "nesbot/carbon",
+            "version": "3.14.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/CarbonPHP/carbon.git",
+                "reference": "94cfc34887f07ab5c0efa07914c8f527544e3224"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/CarbonPHP/carbon/zipball/94cfc34887f07ab5c0efa07914c8f527544e3224",
+                "reference": "94cfc34887f07ab5c0efa07914c8f527544e3224",
+                "shasum": ""
+            },
+            "require": {
+                "carbonphp/carbon-doctrine-types": "<100.0",
+                "ext-json": "*",
+                "php": "^8.1",
+                "psr/clock": "^1.0",
+                "symfony/clock": "^6.3.12 || ^7.0 || ^8.0",
+                "symfony/polyfill-mbstring": "^1.0",
+                "symfony/translation": "^4.4.18 || ^5.2.1 || ^6.0 || ^7.0 || ^8.0"
+            },
+            "provide": {
+                "psr/clock-implementation": "1.0"
+            },
+            "require-dev": {
+                "doctrine/dbal": "^3.6.3 || ^4.0",
+                "doctrine/orm": "^2.15.2 || ^3.0",
+                "friendsofphp/php-cs-fixer": "^v3.87.1",
+                "kylekatarnls/multi-tester": "^2.5.3",
+                "phpmd/phpmd": "^3.0@dev",
+                "phpstan/extension-installer": "^1.4.3",
+                "phpstan/phpstan": "^2.1.22",
+                "phpunit/phpunit": "^10.5.53",
+                "squizlabs/php_codesniffer": "^3.13.4 || ^4.0.0"
+            },
+            "bin": [
+                "bin/carbon"
+            ],
+            "type": "library",
+            "extra": {
+                "laravel": {
+                    "providers": [
+                        "Carbon\\Laravel\\ServiceProvider"
+                    ]
+                },
+                "phpstan": {
+                    "includes": [
+                        "extension.neon"
+                    ]
+                },
+                "branch-alias": {
+                    "dev-2.x": "2.x-dev",
+                    "dev-master": "3.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Carbon\\": "src/Carbon/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Brian Nesbitt",
+                    "email": "brian@nesbot.com",
+                    "homepage": "https://markido.com"
+                },
+                {
+                    "name": "kylekatarnls",
+                    "homepage": "https://github.com/kylekatarnls"
+                }
+            ],
+            "description": "An API extension for DateTime that supports 281 different languages.",
+            "homepage": "https://carbonphp.github.io/carbon/",
+            "keywords": [
+                "date",
+                "datetime",
+                "time"
+            ],
+            "support": {
+                "docs": "https://carbonphp.github.io/carbon/guide/getting-started/introduction.html",
+                "issues": "https://github.com/CarbonPHP/carbon/issues",
+                "source": "https://github.com/CarbonPHP/carbon"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/sponsors/kylekatarnls",
+                    "type": "github"
+                },
+                {
+                    "url": "https://opencollective.com/Carbon#sponsor",
+                    "type": "opencollective"
+                },
+                {
+                    "url": "https://tidelift.com/subscription/pkg/packagist-nesbot-carbon?utm_source=packagist-nesbot-carbon&utm_medium=referral&utm_campaign=readme",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-10-02T07:26:52+00:00"
+        },
+        {
+            "name": "psr/clock",
+            "version": "1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/clock.git",
+                "reference": "e41a24703d4560fd0acb709162f73b8adfc3aa0d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/clock/zipball/e41a24703d4560fd0acb709162f73b8adfc3aa0d",
+                "reference": "e41a24703d4560fd0acb709162f73b8adfc3aa0d",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^7.0 || ^8.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Clock\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for reading the clock.",
+            "homepage": "https://github.com/php-fig/clock",
+            "keywords": [
+                "clock",
+                "now",
+                "psr",
+                "psr-20",
+                "time"
+            ],
+            "support": {
+                "issues": "https://github.com/php-fig/clock/issues",
+                "source": "https://github.com/php-fig/clock/tree/1.0.0"
+            },
+            "time": "2022-11-25T14:36:26+00:00"
+        },
+        {
+            "name": "psr/container",
+            "version": "2.0.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/container.git",
+                "reference": "c71ecc56dfe541dbd90c5360474fbc405f8d5963"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/container/zipball/c71ecc56dfe541dbd90c5360474fbc405f8d5963",
+                "reference": "c71ecc56dfe541dbd90c5360474fbc405f8d5963",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.4.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Container\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common Container Interface (PHP FIG PSR-11)",
+            "homepage": "https://github.com/php-fig/container",
+            "keywords": [
+                "PSR-11",
+                "container",
+                "container-interface",
+                "container-interop",
+                "psr"
+            ],
+            "support": {
+                "issues": "https://github.com/php-fig/container/issues",
+                "source": "https://github.com/php-fig/container/tree/2.0.2"
+            },
+            "time": "2021-11-05T16:47:00+00:00"
+        },
+        {
+            "name": "psr/simple-cache",
+            "version": "3.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/simple-cache.git",
+                "reference": "764e0b3939f5ca87cb904f570ef9be2d78a07865"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/simple-cache/zipball/764e0b3939f5ca87cb904f570ef9be2d78a07865",
+                "reference": "764e0b3939f5ca87cb904f570ef9be2d78a07865",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.0.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\SimpleCache\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "https://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interfaces for simple caching",
+            "keywords": [
+                "cache",
+                "caching",
+                "psr",
+                "psr-16",
+                "simple-cache"
+            ],
+            "support": {
+                "source": "https://github.com/php-fig/simple-cache/tree/3.0.0"
+            },
+            "time": "2021-10-29T13:26:27+00:00"
+        },
+        {
+            "name": "symfony/clock",
+            "version": "v8.1.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/clock.git",
+                "reference": "701ef4de9705d6c32292ebee5e8044094a09fbf6"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/clock/zipball/701ef4de9705d6c32292ebee5e8044094a09fbf6",
+                "reference": "701ef4de9705d6c32292ebee5e8044094a09fbf6",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.4.1",
+                "psr/clock": "^1.0"
+            },
+            "provide": {
+                "psr/clock-implementation": "1.0"
+            },
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "Resources/now.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Component\\Clock\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Decouples applications from the system clock",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "clock",
+                "psr20",
+                "time"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/clock/tree/v8.1.0"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-05-29T05:06:50+00:00"
+        },
+        {
+            "name": "symfony/deprecation-contracts",
+            "version": "v3.7.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/deprecation-contracts.git",
+                "reference": "f3202fa1b5097b0af062dc978b32ecf63404e31d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/deprecation-contracts/zipball/f3202fa1b5097b0af062dc978b32ecf63404e31d",
+                "reference": "f3202fa1b5097b0af062dc978b32ecf63404e31d",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.1"
+            },
+            "type": "library",
+            "extra": {
+                "thanks": {
+                    "url": "https://github.com/symfony/contracts",
+                    "name": "symfony/contracts"
+                },
+                "branch-alias": {
+                    "dev-main": "3.7-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "function.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "A generic function and convention to trigger deprecation notices",
+            "homepage": "https://symfony.com",
+            "support": {
+                "source": "https://github.com/symfony/deprecation-contracts/tree/v3.7.1"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-06-05T06:23:12+00:00"
+        },
+        {
+            "name": "symfony/http-foundation",
+            "version": "v8.1.8",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/http-foundation.git",
+                "reference": "662f5257658d4f60deff1bc790e9f2c68cb391bf"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/http-foundation/zipball/662f5257658d4f60deff1bc790e9f2c68cb391bf",
+                "reference": "662f5257658d4f60deff1bc790e9f2c68cb391bf",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.4.1",
+                "symfony/deprecation-contracts": "^2.5|^3",
+                "symfony/polyfill-mbstring": "^1.1"
+            },
+            "conflict": {
+                "doctrine/dbal": "<4.3"
+            },
+            "require-dev": {
+                "doctrine/dbal": "^4.3",
+                "predis/predis": "^1.1|^2.0",
+                "symfony/cache": "^7.4|^8.0",
+                "symfony/clock": "^7.4|^8.0",
+                "symfony/dependency-injection": "^7.4|^8.0",
+                "symfony/expression-language": "^7.4|^8.0",
+                "symfony/http-kernel": "^7.4|^8.0",
+                "symfony/mime": "^7.4|^8.0",
+                "symfony/rate-limiter": "^7.4|^8.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Component\\HttpFoundation\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Defines an object-oriented layer for the HTTP specification",
+            "homepage": "https://symfony.com",
+            "support": {
+                "source": "https://github.com/symfony/http-foundation/tree/v8.1.8"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-09-24T07:13:53+00:00"
+        },
+        {
+            "name": "symfony/polyfill-mbstring",
+            "version": "v1.43.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-mbstring.git",
+                "reference": "4d5d331bf731e0aedbc6b2f5e61135b7b7996a72"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/4d5d331bf731e0aedbc6b2f5e61135b7b7996a72",
+                "reference": "4d5d331bf731e0aedbc6b2f5e61135b7b7996a72",
+                "shasum": ""
+            },
+            "require": {
+                "ext-iconv": "*",
+                "php": ">=7.2"
+            },
+            "provide": {
+                "ext-mbstring": "*"
+            },
+            "suggest": {
+                "ext-mbstring": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "thanks": {
+                    "url": "https://github.com/symfony/polyfill",
+                    "name": "symfony/polyfill"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Polyfill\\Mbstring\\": ""
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill for the Mbstring extension",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "mbstring",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/polyfill-mbstring/tree/v1.43.0"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-09-24T15:19:04+00:00"
+        },
+        {
+            "name": "symfony/polyfill-php84",
+            "version": "v1.43.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-php84.git",
+                "reference": "22c6548499cbe5c5bb072fc0c42312dff062a015"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-php84/zipball/22c6548499cbe5c5bb072fc0c42312dff062a015",
+                "reference": "22c6548499cbe5c5bb072fc0c42312dff062a015",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.2"
+            },
+            "type": "library",
+            "extra": {
+                "thanks": {
+                    "url": "https://github.com/symfony/polyfill",
+                    "name": "symfony/polyfill"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Polyfill\\Php84\\": ""
+                },
+                "classmap": [
+                    "Resources/stubs"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill backporting some PHP 8.4+ features to lower PHP versions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/polyfill-php84/tree/v1.43.0"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-09-23T22:01:09+00:00"
+        },
+        {
+            "name": "symfony/polyfill-php85",
+            "version": "v1.43.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-php85.git",
+                "reference": "86a42cbcc07adc331481a5ab310a4024bfc227f6"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-php85/zipball/86a42cbcc07adc331481a5ab310a4024bfc227f6",
+                "reference": "86a42cbcc07adc331481a5ab310a4024bfc227f6",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.2"
+            },
+            "type": "library",
+            "extra": {
+                "thanks": {
+                    "url": "https://github.com/symfony/polyfill",
+                    "name": "symfony/polyfill"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Polyfill\\Php85\\": ""
+                },
+                "classmap": [
+                    "Resources/stubs"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill backporting some PHP 8.5+ features to lower PHP versions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/polyfill-php85/tree/v1.43.0"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-09-25T15:46:47+00:00"
+        },
+        {
+            "name": "symfony/polyfill-php86",
+            "version": "v1.43.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-php86.git",
+                "reference": "8840df45b24f33a49dc419fa18dc0057231ae1d8"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-php86/zipball/8840df45b24f33a49dc419fa18dc0057231ae1d8",
+                "reference": "8840df45b24f33a49dc419fa18dc0057231ae1d8",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.2"
+            },
+            "type": "library",
+            "extra": {
+                "thanks": {
+                    "url": "https://github.com/symfony/polyfill",
+                    "name": "symfony/polyfill"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "bootstrap.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Polyfill\\Php86\\": ""
+                },
+                "classmap": [
+                    "Resources/stubs"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill backporting some PHP 8.6+ features to lower PHP versions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/polyfill-php86/tree/v1.43.0"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-09-25T15:46:47+00:00"
+        },
+        {
+            "name": "symfony/translation",
+            "version": "v8.1.5",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/translation.git",
+                "reference": "d9e1caba0d6b6f9a26710af8a2f88d37f001215a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/translation/zipball/d9e1caba0d6b6f9a26710af8a2f88d37f001215a",
+                "reference": "d9e1caba0d6b6f9a26710af8a2f88d37f001215a",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.4.1",
+                "symfony/polyfill-mbstring": "^1.0",
+                "symfony/translation-contracts": "^3.6.1"
+            },
+            "conflict": {
+                "nikic/php-parser": "<5.0",
+                "symfony/http-client-contracts": "<2.5",
+                "symfony/service-contracts": "<2.5"
+            },
+            "provide": {
+                "symfony/translation-implementation": "2.3|3.0"
+            },
+            "require-dev": {
+                "nikic/php-parser": "^5.0",
+                "psr/log": "^1|^2|^3",
+                "symfony/config": "^7.4|^8.0",
+                "symfony/console": "^7.4|^8.0",
+                "symfony/dependency-injection": "^7.4|^8.0",
+                "symfony/finder": "^7.4|^8.0",
+                "symfony/http-client-contracts": "^2.5|^3.0",
+                "symfony/http-kernel": "^7.4|^8.0",
+                "symfony/intl": "^7.4|^8.0",
+                "symfony/polyfill-intl-icu": "^1.21",
+                "symfony/routing": "^7.4|^8.0",
+                "symfony/service-contracts": "^2.5|^3",
+                "symfony/yaml": "^7.4|^8.0"
+            },
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "Resources/functions.php"
+                ],
+                "psr-4": {
+                    "Symfony\\Component\\Translation\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Tests/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Provides tools to internationalize your application",
+            "homepage": "https://symfony.com",
+            "support": {
+                "source": "https://github.com/symfony/translation/tree/v8.1.5"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-08-21T17:47:34+00:00"
+        },
+        {
+            "name": "symfony/translation-contracts",
+            "version": "v3.7.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/translation-contracts.git",
+                "reference": "ccb206b98faccc511ebae8e5fad50f2dc0b30621"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/translation-contracts/zipball/ccb206b98faccc511ebae8e5fad50f2dc0b30621",
+                "reference": "ccb206b98faccc511ebae8e5fad50f2dc0b30621",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=8.1"
+            },
+            "type": "library",
+            "extra": {
+                "thanks": {
+                    "url": "https://github.com/symfony/contracts",
+                    "name": "symfony/contracts"
+                },
+                "branch-alias": {
+                    "dev-main": "3.7-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Contracts\\Translation\\": ""
+                },
+                "exclude-from-classmap": [
+                    "/Test/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Generic abstractions related to translation",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "abstractions",
+                "contracts",
+                "decoupling",
+                "interfaces",
+                "interoperability",
+                "standards"
+            ],
+            "support": {
+                "source": "https://github.com/symfony/translation-contracts/tree/v3.7.1"
+            },
+            "funding": [
+                {
+                    "url": "https://symfony.com/sponsor",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/fabpot",
+                    "type": "github"
+                },
+                {
+                    "url": "https://github.com/nicolas-grekas",
+                    "type": "github"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/symfony/symfony",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-06-05T06:23:12+00:00"
+        },
+        {
+            "name": "voku/portable-ascii",
+            "version": "2.1.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/voku/portable-ascii.git",
+                "reference": "8e1051fe39379367aecf014f41744ce7539a856f"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/voku/portable-ascii/zipball/8e1051fe39379367aecf014f41744ce7539a856f",
+                "reference": "8e1051fe39379367aecf014f41744ce7539a856f",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.1.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~8.5 || ~9.6 || ~10.5 || ~11.5"
+            },
+            "suggest": {
+                "ext-intl": "Use Intl for transliterator_transliterate() support"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "voku\\": "src/voku/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Lars Moelleken",
+                    "homepage": "https://www.moelleken.org/"
+                }
+            ],
+            "description": "Portable ASCII library - performance optimized (ascii) string functions for php.",
+            "homepage": "https://github.com/voku/portable-ascii",
+            "keywords": [
+                "ascii",
+                "clean",
+                "php"
+            ],
+            "support": {
+                "issues": "https://github.com/voku/portable-ascii/issues",
+                "source": "https://github.com/voku/portable-ascii/tree/2.1.1"
+            },
+            "funding": [
+                {
+                    "url": "https://www.paypal.me/moelleken",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/voku",
+                    "type": "github"
+                },
+                {
+                    "url": "https://opencollective.com/portable-ascii",
+                    "type": "open_collective"
+                },
+                {
+                    "url": "https://www.patreon.com/voku",
+                    "type": "patreon"
+                },
+                {
+                    "url": "https://tidelift.com/funding/github/packagist/voku/portable-ascii",
+                    "type": "tidelift"
+                }
+            ],
+            "time": "2026-04-26T05:33:54+00:00"
+        },
+        {
+            "name": "webklex/php-imap",
+            "version": "6.2.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/Webklex/php-imap.git",
+                "reference": "6b8ef85d621bbbaf52741b00cca8e9237e2b2e05"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/Webklex/php-imap/zipball/6b8ef85d621bbbaf52741b00cca8e9237e2b2e05",
+                "reference": "6b8ef85d621bbbaf52741b00cca8e9237e2b2e05",
+                "shasum": ""
+            },
+            "require": {
+                "ext-fileinfo": "*",
+                "ext-iconv": "*",
+                "ext-json": "*",
+                "ext-libxml": "*",
+                "ext-mbstring": "*",
+                "ext-openssl": "*",
+                "ext-zip": "*",
+                "illuminate/pagination": ">=5.0.0",
+                "nesbot/carbon": "^2.62.1|^3.2.4",
+                "php": "^8.0.2",
+                "symfony/http-foundation": ">=2.8.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^9.5.10"
+            },
+            "suggest": {
+                "symfony/mime": "Recomended for better extension support",
+                "symfony/var-dumper": "Usefull tool for debugging"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "6.0-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Webklex\\PHPIMAP\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Malte Goldenbaum",
+                    "email": "github@webklex.com",
+                    "role": "Developer"
+                }
+            ],
+            "description": "PHP IMAP client",
+            "homepage": "https://github.com/webklex/php-imap",
+            "keywords": [
+                "imap",
+                "mail",
+                "php-imap",
+                "pop3",
+                "webklex"
+            ],
+            "support": {
+                "issues": "https://github.com/Webklex/php-imap/issues",
+                "source": "https://github.com/Webklex/php-imap/tree/6.2.0"
+            },
+            "funding": [
+                {
+                    "url": "https://www.buymeacoffee.com/webklex",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://ko-fi.com/webklex",
+                    "type": "ko_fi"
+                }
+            ],
+            "time": "2025-04-25T06:02:37+00:00"
+        }
+    ],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": {},
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": {},
+    "platform-dev": {},
+    "plugin-api-version": "2.6.0"
+}
diff --git a/config.php b/config.php
new file mode 100644
index 0000000..d6d7086
--- /dev/null
+++ b/config.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+// Operational settings: edit this file over SSH, then allow the next cron/request
+// to load it. Mailbox credentials and helpdesk mappings stay in the settings page.
+return [
+    'poll_interval_seconds' => 300,
+    'messages_per_mailbox' => 50,
+    'poll_budget_seconds' => 90,
+    'imap_timeout_seconds' => 15,
+    'max_message_bytes' => 5 * 1024 * 1024,
+    'max_ticket_body_bytes' => 65535, // Cannot exceed Support's TEXT column limit.
+    'notification_cooldown_seconds' => 3600,
+    'composer_timeout_seconds' => 60,
+    'php_cli_paths' => [PHP_BINDIR . '/php' . PHP_MAJOR_VERSION . '.' . PHP_MINOR_VERSION, PHP_BINDIR . '/php'],
+    'composer_paths' => ['/usr/local/bin/composer', '/usr/bin/composer'],
+];
diff --git a/schema.sql b/schema.sql
new file mode 100644
index 0000000..45dc214
--- /dev/null
+++ b/schema.sql
@@ -0,0 +1,20 @@
+CREATE TABLE IF NOT EXISTS mailgateway_message (
+    message_key CHAR(64) CHARACTER SET ascii COLLATE ascii_bin NOT NULL PRIMARY KEY,
+    mailbox VARCHAR(255) NOT NULL,
+    message_id VARCHAR(998) NOT NULL,
+    payload_hash CHAR(64) CHARACTER SET ascii COLLATE ascii_bin NOT NULL,
+    ticket_id INT DEFAULT NULL,
+    result_json TEXT DEFAULT NULL,
+    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    INDEX mailgateway_ticket (ticket_id)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+CREATE TABLE IF NOT EXISTS mailgateway_notification (
+    sender_key CHAR(64) CHARACTER SET ascii COLLATE ascii_bin NOT NULL PRIMARY KEY,
+    last_notified_at BIGINT NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+CREATE TABLE IF NOT EXISTS mailgateway_settings (
+    id SMALLINT NOT NULL PRIMARY KEY,
+    config_encrypted TEXT NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
diff --git a/templates/admin/mod_mailgateway_settings.html.twig b/templates/admin/mod_mailgateway_settings.html.twig
new file mode 100644
index 0000000..07c79ed
--- /dev/null
+++ b/templates/admin/mod_mailgateway_settings.html.twig
@@ -0,0 +1,192 @@
+{% extends request.ajax ? 'layout_blank.html.twig' : 'layout_default.html.twig' %}
+{% block meta_title %}{{ 'Mail Gateway Settings'|trans }}{% endblock %}
+{% set active_menu = 'system' %}
+{% set result = admin.mailgateway_settings_get({}) %}
+{% set params = result.settings %}
+
+{% block content %}
+{% if result.notifications is defined %}
+<div id="mg-notification-banner" data-ready="{{ result.notifications.ready ? '1' : '0' }}" class="alert {{ result.notifications.ready ? 'alert-success' : 'alert-warning' }}" {% if result.notifications.ready %}hidden{% endif %}>
+    {% if result.notifications.ready %}
+        {{ 'Ticket acknowledgement and enabled staff notification subjects are configured for email replies.'|trans }}
+    {% else %}
+        <p>{{ 'Ticket notifications need configuration. Enabling mailbox importing will configure them automatically, or use Advanced below.'|trans }}</p>
+        <ul>{% for error in result.notifications.errors %}<li>{{ error }}</li>{% endfor %}</ul>
+    {% endif %}
+</div>
+{% endif %}
+{% if result.dependencies is defined and not result.dependencies.installed %}
+<div class="card mb-3">
+    <div class="card-body">
+        {% if result.dependencies.available %}
+            <p>{{ 'Install the required mail library before testing connections or enabling imports.'|trans }}</p>
+            <form action="{{ 'mailgateway/install_dependencies'|api_url(role: 'admin') }}" {{ fb_api_form({message: 'Mail Gateway dependencies installed'|trans, reload: true, timeoutMs: result.dependencies.request_timeout_ms|default(90000), loading: {button: 'Installing dependencies…'|trans}, preventNavigation: true}) }}>
+                <button class="btn btn-primary" type="submit">{{ 'Install dependencies'|trans }}</button>
+            </form>
+        {% else %}
+            <p>{{ 'Automatic installation is unavailable on this server. Run composer install from the Mailgateway directory using SSH.'|trans }}</p>
+        {% endif %}
+    </div>
+</div>
+{% endif %}
+<button class="btn btn-primary mb-3" type="button" onclick="document.getElementById('mg-new').hidden = false; this.hidden = true">{{ 'Add mailbox'|trans }}</button>
+{% set mailboxes = result.mailboxes is defined ? result.mailboxes : {'default': result.settings} %}
+{% set newMailbox = result.settings|merge({'password_configured': false, 'enabled': false, 'mailbox': '', 'username': '', 'test_passed': false, 'test_result': null}) %}
+{% for mailboxId, params in mailboxes|merge({'new': newMailbox}) %}
+{% set canEnable = result.dependencies.installed|default(false) and params.test_passed|default(false) %}
+{% set disabledReason = not result.dependencies.installed|default(false) ? 'Install dependencies before enabling mailbox importing.'|trans : 'Save this mailbox, then run Test Connection and Create Folders successfully before enabling importing. Connection, password, or folder changes require another test.'|trans %}
+<div class="card mb-3" id="mg-{{ mailboxId }}" {% if mailboxId == 'new' %}hidden{% endif %}>
+    <div class="card-header"><h3 class="card-title">{{ mailboxId == 'new' ? 'New mailbox'|trans : params.mailbox }}</h3></div>
+    <form method="post" action="{{ 'mailgateway/settings_save'|api_url(role: 'admin') }}" {{ fb_api_form({message: 'Mail Gateway settings saved'|trans, reload: true}) }}>
+        <input type="hidden" name="mailbox_id" value="{{ mailboxId }}">
+        <div class="card-body">
+            <p class="text-secondary">{{ 'Each enabled mailbox routes new tickets to its selected helpdesk. The existing FOSSBilling cron polls mailboxes at the interval defined in the module configuration file.'|trans }}</p>
+            <div class="mb-3">
+                <label class="form-check form-switch" id="mg-enable-label-{{ mailboxId }}" {% if not canEnable %}title="{{ disabledReason }}"{% endif %}>
+                    <input type="hidden" name="enabled" value="0">
+                    <input class="form-check-input" id="mg-enabled-{{ mailboxId }}" type="checkbox" name="enabled" value="1" aria-describedby="mg-enable-hint-{{ mailboxId }}" {% if params.enabled and canEnable %}checked{% endif %} {% if not canEnable %}disabled{% endif %}>
+                    <span class="form-check-label">{{ 'Enable mailbox importing'|trans }}</span>
+                </label>
+                <small class="form-hint" id="mg-enable-hint-{{ mailboxId }}">{% if not canEnable %}{{ disabledReason }}{% endif %}</small>
+            </div>
+            <div class="row g-3">
+                <div class="col-md-8"><label class="form-label" for="mg-{{ mailboxId }}-host">{{ 'IMAP host'|trans }}</label><input class="form-control" id="mg-{{ mailboxId }}-host" name="host" value="{{ params.host }}" maxlength="255" required></div>
+                <div class="col-md-4"><label class="form-label" for="mg-{{ mailboxId }}-port">{{ 'Port'|trans }}</label><input class="form-control" id="mg-{{ mailboxId }}-port" name="port" type="number" min="1" max="65535" value="{{ params.port }}" required></div>
+                <div class="col-md-6">
+                    <label class="form-label" for="mg-{{ mailboxId }}-encryption">{{ 'Connection security'|trans }}</label>
+                    <select class="form-select" id="mg-{{ mailboxId }}-encryption" name="encryption"><option value="ssl" {% if params.encryption == 'ssl' %}selected{% endif %}>{{ 'Implicit TLS (usually port 993)'|trans }}</option><option value="tls" {% if params.encryption == 'tls' %}selected{% endif %}>{{ 'STARTTLS (usually port 143)'|trans }}</option></select>
+                    <small class="form-hint">{{ 'TLS certificate validation is always enabled.'|trans }}</small>
+                </div>
+                <div class="col-md-6"><label class="form-label" for="mg-{{ mailboxId }}-mailbox">{{ 'Mailbox email address'|trans }}</label><input class="form-control" id="mg-{{ mailboxId }}-mailbox" name="mailbox" type="email" value="{{ params.mailbox }}" maxlength="255" required></div>
+                <div class="col-md-6"><label class="form-label" for="mg-{{ mailboxId }}-username">{{ 'IMAP username'|trans }}</label><input class="form-control" id="mg-{{ mailboxId }}-username" name="username" value="{{ params.username }}" maxlength="255" autocomplete="off" required></div>
+                <div class="col-md-6">
+                    <label class="form-label" for="mg-{{ mailboxId }}-password">{{ 'Mailbox password'|trans }}</label>
+                    <input class="form-control" id="mg-{{ mailboxId }}-password" name="password" type="password" autocomplete="new-password" maxlength="4096">
+                    <small class="form-hint">{% if params.password_configured %}{{ 'A password is saved. Leave blank to keep it.'|trans }}{% else %}{{ 'No password is saved.'|trans }}{% endif %}</small>
+                    <label class="form-check mt-2"><input class="form-check-input" name="clear_password" type="checkbox" value="1"><span class="form-check-label">{{ 'Clear the saved password'|trans }}</span></label>
+                </div>
+                <div class="col-12">
+                    <label class="form-label" for="mg-{{ mailboxId }}-helpdesk">{{ 'Support helpdesk'|trans }}</label>
+                    <select class="form-select" id="mg-{{ mailboxId }}-helpdesk" name="support_helpdesk_id" required>
+                        <option value="">{{ 'Choose a helpdesk'|trans }}</option>
+                        {% for id, name in result.helpdesks %}<option value="{{ id }}" {% if params.support_helpdesk_id == id or (params.support_helpdesk_id is null and name == 'General') %}selected{% endif %}>{{ name }}</option>{% endfor %}
+                    </select>
+                </div>
+                {% for field, label in {'inbox_folder': 'Inbox folder', 'processed_folder': 'Processed folder', 'ignored_folder': 'Ignored folder', 'failed_folder': 'Failed folder'} %}
+                    <div class="col-md-6"><label class="form-label" for="mg-{{ mailboxId }}-{{ field }}">{{ label|trans }}</label><input class="form-control" id="mg-{{ mailboxId }}-{{ field }}" name="{{ field }}" value="{{ attribute(params, field) }}" maxlength="255" required></div>
+                {% endfor %}
+            </div>
+            <p class="form-hint mt-3">{{ 'Only the configured inbox is imported. Keep spam in a separate folder. Enabled mailboxes are imported automatically by FOSSBilling cron.'|trans }}</p>
+        </div>
+        <div class="card-footer"><button class="btn btn-primary" type="submit">{{ 'Save settings'|trans }}</button></div>
+    </form>
+    {% if mailboxId != 'new' %}
+    <div class="card-footer">
+        <form action="{{ 'mailgateway/mailbox_delete'|api_url(role: 'admin') }}" {{ fb_api_form({message: 'Mailbox removed'|trans, reload: true}) }} data-confirm="{{ 'Remove the saved configuration for %mailbox%? Emails, folders, tickets, and message tracking will be kept.'|trans|replace({'%mailbox%': params.mailbox}) }}" onsubmit="if (!confirm(this.dataset.confirm)) { event.preventDefault(); event.stopImmediatePropagation(); return false; }">
+            <input type="hidden" name="mailbox_id" value="{{ mailboxId }}">
+            <button class="btn btn-outline-danger" type="submit">{{ 'Delete mailbox'|trans }}</button>
+        </form>
+    </div>
+    <div class="card-footer">
+        <button class="btn btn-secondary" type="button" onclick="mailgatewayTest('{{ mailboxId }}')" {% if not result.dependencies.installed|default(false) %}disabled{% endif %}>{{ 'Test Connection and Create Folders'|trans }}</button>
+        <small class="text-secondary">{{ 'Tests saved settings and creates missing destination folders. Save changes first. No mail is imported or moved.'|trans }}</small>
+        <pre class="mt-2 mb-0" style="white-space: pre-wrap" id="mg-result-{{ mailboxId }}" role="status">{% if params.test_result|default(null) %}{{ params.test_result.connected ? 'IMAP login succeeded.'|trans : 'IMAP login failed.'|trans }}
+{% if params.test_result.move_supported is defined and params.test_result.move_supported %}{{ 'Native MOVE support: available.'|trans }}
+{% endif %}{% for folder in params.test_result.folders %}{{ folder.path }}: {{ folder.error ?: (folder.created ? 'created'|trans : 'found'|trans) }}
+{% endfor %}{% for error in params.test_result.errors %}{{ error }}
+{% endfor %}{{ params.test_result.success ? 'Test passed. You can enable importing and save.'|trans : 'Importing remains disabled until all checks pass.'|trans }}{% endif %}</pre>
+    </div>
+    {% endif %}
+</div>
+{% endfor %}
+<details class="card mb-3">
+    <summary class="card-header">{{ 'Advanced'|trans }}</summary>
+    <div class="card-body">
+        <p class="text-secondary">{{ 'Maintenance actions preserve saved mailbox settings and existing ticket data.'|trans }}</p>
+        {% if result.notifications is defined %}
+        <div class="mb-4">
+            <h4>{{ 'Ticket notifications'|trans }}</h4>
+            {% if result.notifications.ready %}
+                <p class="text-success">{{ 'Ticket acknowledgement and enabled staff notification subjects are configured for email replies.'|trans }}</p>
+            {% else %}
+                <ul>{% for error in result.notifications.errors %}<li>{{ error }}</li>{% endfor %}</ul>
+            {% endif %}
+            <p>{{ 'Setup enables the ticket acknowledgement and adds ticket numbers to its subject and enabled staff notification subjects. Existing wording is kept.'|trans }}</p>
+            <form action="{{ 'mailgateway/notifications_setup'|api_url(role: 'admin') }}" {{ fb_api_form({message: 'Ticket notifications configured'|trans, reload: true}) }}>
+                <button class="btn btn-secondary" type="submit">{{ 'Configure ticket notifications'|trans }}</button>
+            </form>
+        </div>
+        {% endif %}
+        <div class="mb-4">
+            <h4>{{ 'Composer dependencies'|trans }}</h4>
+            {% if result.dependencies.installed|default(false) %}
+                <p class="text-success">{{ 'Mail Gateway dependencies are installed.'|trans }}</p>
+            {% else %}
+                <p>{{ 'Mail Gateway dependencies are not installed.'|trans }}</p>
+            {% endif %}
+            <p>{{ 'Run composer install again using the module lock file, even when dependencies are already installed.'|trans }}</p>
+            {% if result.dependencies is defined and result.dependencies.available %}
+            <form action="{{ 'mailgateway/install_dependencies'|api_url(role: 'admin') }}" {{ fb_api_form({message: 'Composer install completed'|trans, reload: true, timeoutMs: result.dependencies.request_timeout_ms|default(90000), loading: {button: 'Running Composer…'|trans}, preventNavigation: true}) }}>
+                <input type="hidden" name="force" value="1">
+                <button class="btn btn-secondary" type="submit">{{ 'Run composer install'|trans }}</button>
+            </form>
+            {% else %}
+                <p>{{ 'Web installation is unavailable. Run composer install from the Mailgateway directory using SSH.'|trans }}</p>
+            {% endif %}
+        </div>
+        <div>
+            <h4>{{ 'Module table setup'|trans }}</h4>
+            <p>{{ 'Runs the same setup as php tools/setup.php. Creates missing module tables and adds the default mismatch email template if absent. Existing records and templates are kept. Composer runs separately.'|trans }}</p>
+            <form action="{{ 'mailgateway/setup'|api_url(role: 'admin') }}" {{ fb_api_form({message: 'Mail Gateway table setup completed'|trans, reload: true, loading: {button: 'Running setup…'|trans}}) }}>
+                <button class="btn btn-secondary" type="submit">{{ 'Run table setup'|trans }}</button>
+            </form>
+        </div>
+    </div>
+</details>
+<script>
+(function() {
+    const banner = document.getElementById('mg-notification-banner');
+    if (!banner) return;
+    try {
+        const key = 'mailgateway.notificationErrors:' + location.pathname;
+        if (banner.dataset.ready === '0') {
+            sessionStorage.setItem(key, '1');
+        } else {
+            banner.hidden = sessionStorage.getItem(key) !== '1';
+            sessionStorage.removeItem(key);
+        }
+    } catch (error) { /* The persistent status remains available in Advanced. */ }
+})();
+document.querySelectorAll('input[name="mailbox_id"]').forEach(function(hidden) {
+    const form = hidden.form;
+    const id = hidden.value;
+    form.addEventListener('input', function(event) {
+        if (!['host', 'port', 'encryption', 'username', 'password', 'clear_password', 'mailbox', 'inbox_folder', 'processed_folder', 'ignored_folder', 'failed_folder'].includes(event.target.name)) return;
+        const checkbox = document.getElementById('mg-enabled-' + id);
+        checkbox.disabled = true;
+        checkbox.checked = false;
+        const reason = 'Save the changed mailbox settings, then run Test Connection and Create Folders again.';
+        document.getElementById('mg-enable-label-' + id).title = reason;
+        document.getElementById('mg-enable-hint-' + id).textContent = reason;
+    });
+});
+function mailgatewayTest(id) {
+    const output = document.getElementById('mg-result-' + id);
+    output.textContent = 'Testing connection and creating missing destination folders…';
+    FOSSBilling.api.admin.post('mailgateway/test_connection', {mailbox_id: id}, function(result) {
+        output.textContent = (result.connected ? 'IMAP login succeeded.' : 'IMAP login failed.') + '\n'
+            + (result.move_supported ? 'Native MOVE support: available.\n' : '')
+            + result.folders.map(function(folder) {
+                return folder.path + ': ' + (folder.error || (folder.created ? 'created' : (folder.exists ? 'found' : 'MISSING')));
+            }).concat(result.errors).join('\n') + '\n'
+            + (result.success ? 'Test passed. You can enable importing and save.' : 'Importing remains disabled until all checks pass.');
+        const checkbox = document.getElementById('mg-enabled-' + id);
+        checkbox.disabled = !result.success;
+        if (!result.success) checkbox.checked = false;
+        const reason = result.success ? '' : 'Fix the reported issues, then run Test Connection and Create Folders again.';
+        document.getElementById('mg-enable-label-' + id).title = reason;
+        document.getElementById('mg-enable-hint-' + id).textContent = reason;
+    }, function(error) { output.textContent = error.message || 'Connection test or folder creation failed.'; });
+}
+</script>
+{% endblock %}
diff --git a/templates/email/mailgateway_sender_mismatch.html.twig b/templates/email/mailgateway_sender_mismatch.html.twig
new file mode 100644
index 0000000..6cbd941
--- /dev/null
+++ b/templates/email/mailgateway_sender_mismatch.html.twig
@@ -0,0 +1,89 @@
+{% block subject %}[{{ guest.system_company.name }}] Unable to process your support reply{% endblock %}
+{% block content %}
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <style type="text/css">
+        body {
+            font-family: Arial, sans-serif;
+            font-size: 14px;
+            color: #333333;
+            line-height: 1.6;
+        }
+
+        h1 {
+            font-size: 24px;
+            font-weight: bold;
+            margin: 0 0 20px;
+        }
+
+        p {
+            margin: 0 0 15px;
+        }
+
+        .notice {
+            background-color: #f7f7f7;
+            border-left: 4px solid #cc9900;
+            padding: 15px;
+            margin: 20px 0;
+        }
+
+        .signature {
+            font-style: italic;
+            color: #999999;
+            margin-top: 20px;
+            border-top: 1px solid #cccccc;
+            padding-top: 10px;
+        }
+    </style>
+</head>
+<body>
+
+    <h1>We couldn't process your reply</h1>
+
+    <p>Hello,</p>
+
+    <p>
+        Thank you for contacting {{ guest.system_company.name }}.
+    </p>
+
+    <p>
+        Unfortunately, we couldn't add your email to the support ticket
+        you replied to.
+    </p>
+
+    <div class="notice">
+        <p>
+            <strong>Please reply from the email address associated
+            with your account.</strong>
+        </p>
+
+        <p>
+            For security reasons, we can only accept email replies
+            from an address authorised to access the support ticket.
+        </p>
+    </div>
+
+    <p>
+        Your message has not been added to the ticket.
+        Please resend it using your registered email address.
+    </p>
+
+    <p>
+        If you no longer have access to that email address,
+        please log in to your account to update your details
+        or contact us for assistance.
+    </p>
+
+    <p>
+        Kind regards,
+    </p>
+
+    <div class="signature">
+        {{ guest.system_email.signature }}
+    </div>
+
+</body>
+</html>
+{% endblock %}
diff --git a/tests/automatic.php b/tests/automatic.php
new file mode 100644
index 0000000..ba66dc4
--- /dev/null
+++ b/tests/automatic.php
@@ -0,0 +1,82 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/tracking.php';
+
+$policy = new \Box\Mod\Mailgateway\InboundPolicy();
+$cases = [
+    [['auto_submitted' => 'auto-replied'], 'auto_submitted'],
+    [['auto_submitted' => 'Auto-Generated; owner-email="support@example.com"'], 'auto_submitted'],
+    [['headers' => ['AUTO-SUBMITTED' => ['no', 'auto-replied']]], 'auto_submitted'],
+    [['return_path' => '<>'], 'null_return_path'],
+    [['content_type' => 'multipart/report; report-type=delivery-status; boundary=abc'], 'delivery_report'],
+    [['content_type' => 'message/disposition-notification'], 'delivery_report'],
+    [['precedence' => 'bulk'], 'bulk_mail'],
+    [['precedence' => 'LIST'], 'bulk_mail'],
+    [['list_id' => 'Announcements <list.example.com>'], 'mailing_list'],
+    [['x_auto_response_suppress' => 'All'], 'response_suppressed'],
+    [['x_auto_response_suppress' => 'DR, OOF, AutoReply'], 'response_suppressed'],
+    [['x_autoreply' => 'yes'], 'legacy_autoresponder'],
+    [['x_autorespond' => 'true'], 'legacy_autoresponder'],
+];
+$messageCount = (int) $connection->fetchOne('SELECT COUNT(*) FROM test_messages');
+$notifications = $trackingService->notifications;
+foreach ($cases as $index => [$fields, $reason]) {
+    $input = array_merge([
+        'mailbox' => 'support@dev.sebs.space',
+        'message_id' => '<automatic-' . $index . '@example.com>',
+        // Would normally reject this mismatched reply and send a notification.
+        'subject' => 'Re: [Ticket #41] Test',
+        'sender_email' => 'wrong@example.com',
+        'content' => 'Away from the office',
+    ], $fields);
+    $result = $tracker->process($input, $trackingService);
+    if ($result !== ['action' => 'ignored', 'reason' => $reason, 'duplicate' => false]) {
+        throw new RuntimeException('Automatic message was not ignored: ' . $index);
+    }
+    $repeat = $tracker->process($input, $trackingService);
+    if (!$repeat['duplicate'] || $repeat['action'] !== 'ignored') {
+        throw new RuntimeException('Ignored message retry was not deduplicated');
+    }
+    $row = $connection->fetchAssociative('SELECT ticket_id FROM mailgateway_message WHERE message_id = ?', [$input['message_id']]);
+    if (!$row || $row['ticket_id'] !== null) {
+        throw new RuntimeException('Ignored mail acquired a ticket association');
+    }
+    // The underlying service methods must also skip without database or mail access.
+    $guardedService = new \Box\Mod\Mailgateway\Service();
+    foreach (['import', 'reply'] as $method) {
+        if ($guardedService->$method($fields) !== ['action' => 'ignored', 'reason' => $reason]) {
+            throw new RuntimeException('Service method responded to automatic mail');
+        }
+    }
+}
+$minimal = $tracker->process([
+    'mailbox' => 'support@dev.sebs.space', 'message_id' => '<minimal-auto@example.com>',
+    'auto_submitted' => 'auto-replied',
+], $trackingService);
+if ($minimal['action'] !== 'ignored'
+    || (int) $connection->fetchOne('SELECT COUNT(*) FROM test_messages') !== $messageCount
+    || $trackingService->notifications !== $notifications) {
+    throw new RuntimeException('Automatic mail created a message or sent a notification');
+}
+foreach ([[], ['auto_submitted' => 'NO'], ['auto_submitted' => 'no; extension=value'],
+    ['return_path' => '<customer@example.com>'], ['content_type' => 'text/plain; charset=utf-8'],
+    ['x_auto_response_suppress' => 'None'], ['x_autoreply' => 'false']] as $fields) {
+    if ($policy->ignoreReason($policy->headers($fields)) !== null) {
+        throw new RuntimeException('Normal message classified as automatic');
+    }
+}
+$folded = $policy->headers(['headers' => ['Auto-Submitted' => "auto-replied;\r\n owner=test"]]);
+if ($policy->ignoreReason($folded) !== 'auto_submitted') {
+    throw new RuntimeException('Folded header failed');
+}
+try {
+    $policy->headers(['auto_submitted' => "no\r\nInjected: value"]);
+    throw new RuntimeException('Header injection accepted');
+} catch (\FOSSBilling\InformationException) {}
+try {
+    $tracker->process(array_merge($input, ['auto_submitted' => 'no']), $trackingService);
+    throw new RuntimeException('Changed detection headers bypassed deduplication');
+} catch (\FOSSBilling\InformationException) {}
+echo "Passed automatic-message filtering, repeated/mixed/folded headers, ignored-message deduplication, no ticket writes or notifications, service method protection, and normal-mail exceptions.\n";
diff --git a/tests/config.php b/tests/config.php
new file mode 100644
index 0000000..11d36fe
--- /dev/null
+++ b/tests/config.php
@@ -0,0 +1,6 @@
+<?php
+
+declare(strict_types=1);
+
+// Minimal configuration for isolated validation checks; no database or secrets.
+return ['debug_and_monitoring' => ['log_stacktrace' => false]];
diff --git a/tests/cooldown.php b/tests/cooldown.php
new file mode 100644
index 0000000..fc71df5
--- /dev/null
+++ b/tests/cooldown.php
@@ -0,0 +1,115 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/automatic.php';
+$connection->executeStatement('CREATE TABLE mailgateway_notification (sender_key TEXT PRIMARY KEY, last_notified_at INTEGER NOT NULL)');
+$sent = 0;
+$send = function () use (&$sent): bool { ++$sent; return true; };
+$limiter = new \Box\Mod\Mailgateway\NotificationCooldown($connection);
+$newRun = new \Box\Mod\Mailgateway\NotificationCooldown($connection);
+if (!$limiter->run('Guest@example.com', $send) || $newRun->run('guest@example.com', $send) || $sent !== 1) {
+    throw new RuntimeException('New polling run reset cooldown');
+}
+$key = hash('sha256', 'guest@example.com');
+$connection->update('mailgateway_notification', ['last_notified_at' => time() - 300], ['sender_key' => $key]);
+if ($newRun->run('guest@example.com', $send)) {
+    throw new RuntimeException('Five-minute poll bypassed cooldown');
+}
+$connection->update('mailgateway_notification', ['last_notified_at' => time() - 3601], ['sender_key' => $key]);
+if (!$newRun->run('guest@example.com', $send)) {
+    throw new RuntimeException('Expired cooldown did not permit notification');
+}
+if ($limiter->run('disabled@example.com', fn () => false) || !$limiter->run('disabled@example.com', $send)) {
+    throw new RuntimeException('Disabled template consumed cooldown');
+}
+$before = (int) $connection->fetchOne('SELECT COUNT(*) FROM test_messages');
+try {
+    $limiter->run('failure@example.com', function () use ($connection): void {
+        $connection->insert('test_messages', ['ticket_id' => 41]);
+        throw new RuntimeException('Queue failed');
+    });
+    throw new LogicException('Queue failure swallowed');
+} catch (RuntimeException $error) {
+    if ($error->getMessage() !== 'Queue failed') { throw $error; }
+}
+if ((int) $connection->fetchOne('SELECT COUNT(*) FROM test_messages') !== $before || !$limiter->run('failure@example.com', $send)) {
+    throw new RuntimeException('Failed queue did not roll back');
+}
+$connection->beginTransaction();
+$limiter->run('transaction@example.com', $send);
+$connection->rollBack();
+if (!$limiter->run('transaction@example.com', $send)) {
+    throw new RuntimeException('Outer rollback retained cooldown');
+}
+
+$connection->executeStatement('CREATE TABLE client (id INTEGER PRIMARY KEY, email TEXT)');
+$di = new \Pimple\Container();
+$di['dbal'] = $connection;
+$di['mailgateway_settings'] = new class {
+    public function get(): array { return ['support_helpdesk_id' => null]; }
+};
+$di['em'] = new class { public function flush(): void {} public function clear(): void {} };
+$di['logger'] = new class { public function warning(...$args): void {} };
+$mail = new class {
+    public array $emails = [];
+    public function sendTemplate($data): bool { $this->emails[] = $data; return true; }
+};
+$ticket = new \Box\Mod\Support\Entity\SupportTicket();
+(new ReflectionProperty($ticket, 'id'))->setValue($ticket, 50);
+$ticket->setAccessHash('guest-hash');
+$ticket->setAuthorEmail('guest-owner@example.com');
+$support = new class($di, $ticket) {
+    public int $created = 0;
+    public int $replies = 0;
+    public bool $fail = false;
+    public function __construct(public $di, public $ticket) {}
+    public function getHelpdeskRepository() { return $this; }
+    public function findBy($criteria, $order, $limit)
+    {
+        $desk = new \Box\Mod\Support\Entity\Helpdesk();
+        (new ReflectionProperty($desk, 'id'))->setValue($desk, 1);
+        return [$desk];
+    }
+    public function ticketCreateForGuest($data)
+    {
+        ++$this->created;
+        foreach (['mod_support_ticket_open', 'mod_support_ticket_staff_reply'] as $code) {
+            $this->di['mod_service']('email')->sendTemplate(['code' => $code, 'to' => $data['email']]);
+        }
+        if ($this->fail) { throw new RuntimeException('Support failed'); }
+        return 'guest-hash';
+    }
+    public function findOneByHash($hash) { return $this->ticket; }
+    public function getTicketById($id) { return $this->ticket; }
+    public function canBeReopened($ticket): bool { return true; }
+    public function ticketReply($ticket, $identity, $content): int { return ++$this->replies; }
+};
+$lookup = fn ($module, $sub = '') => $module === 'email' ? $mail : $support;
+$di['mod_service'] = $di->protect($lookup);
+$service = new \Box\Mod\Mailgateway\Service();
+$service->setDi($di);
+$input = ['sender_email' => 'guest-owner@example.com', 'subject' => 'Test', 'content' => 'Test body'];
+$service->import($input);
+$service->import($input);
+if ($support->created !== 2 || count($mail->emails) !== 1 || $di['mod_service'] !== $lookup) {
+    throw new RuntimeException('Guest notification cooldown or lookup restoration failed');
+}
+$service->reply(['sender_email' => $input['sender_email'], 'ticket_id' => 50, 'content' => 'Human reply']);
+if ($support->replies !== 1) { throw new RuntimeException('Human reply blocked by cooldown'); }
+foreach ([1, 2] as $attempt) {
+    try {
+        $tracker->process(['mailbox' => 'support@example.com', 'message_id' => "<cooldown-mismatch-$attempt@example.com>",
+            'sender_email' => 'wrong@example.com', 'subject' => '[Ticket #50] Reply', 'content' => 'Mismatch'], $service);
+        throw new RuntimeException('Mismatch accepted');
+    } catch (\FOSSBilling\InformationException) {}
+}
+if (count($mail->emails) !== 2 || $mail->emails[1]['code'] !== 'mailgateway_sender_mismatch') {
+    throw new RuntimeException('Mismatch cooldown failed');
+}
+$support->fail = true;
+try { $service->import($input); } catch (RuntimeException $error) {
+    if ($error->getMessage() !== 'Support failed') { throw $error; }
+}
+if ($di['mod_service'] !== $lookup) { throw new RuntimeException('Failure left email interception active'); }
+echo "Passed persistent cooldown, five-minute polls, expiry, failed/disabled queues, nested rollback, guest acknowledgements, mismatch notifications, human replies, and service restoration.\n";
diff --git a/tests/polling.php b/tests/polling.php
new file mode 100644
index 0000000..94bfd22
--- /dev/null
+++ b/tests/polling.php
@@ -0,0 +1,346 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/settings.php';
+require dirname(__DIR__) . '/Poller.php';
+require dirname(__DIR__) . '/ImapMailbox.php';
+require dirname(__DIR__) . '/vendor/autoload.php';
+
+$pollDb = \Doctrine\DBAL\DriverManager::getConnection(['driver' => 'pdo_sqlite', 'memory' => true]);
+$pollDb->executeStatement('CREATE TABLE mailgateway_message (message_key TEXT PRIMARY KEY, mailbox TEXT, message_id TEXT, payload_hash TEXT, ticket_id INTEGER, result_json TEXT)');
+$pollDb->executeStatement('CREATE TABLE imported (id INTEGER PRIMARY KEY AUTOINCREMENT, kind TEXT)');
+$pollService = new class($pollDb) extends \Box\Mod\Mailgateway\Service {
+    public function __construct(public $connection) {}
+    public function import(array $data): array {
+        if ($data['content'] === 'database failure') { throw new RuntimeException('SECRET infrastructure failure'); }
+        $this->connection->insert('imported', ['kind' => 'ticket']);
+        return ['ticket_id' => 101];
+    }
+    public function reply(array $data): array {
+        if ($data['ticket_id'] === 999) { throw new \FOSSBilling\InformationException('Ticket not found'); }
+        $this->connection->insert('imported', ['kind' => 'reply']);
+        return ['ticket_id' => $data['ticket_id'], 'message_id' => 77];
+    }
+};
+$pollDi = new \Pimple\Container();
+$pollDi['dbal'] = $pollDb;
+$pollDi['em'] = new class { public function clear() {} };
+$pollDi['logger'] = new class {
+    public array $logs = [];
+    public function warning($text) { $this->logs[] = $text; }
+    public function info($text) { $this->logs[] = $text; }
+};
+$system = new class {
+    public $last = 0;
+    public function getParamValue($key, $default) { return $this->last; }
+    public function setParamValue($key, $value, $create) { $this->last = $value; }
+};
+$enabled = array_replace(\Box\Mod\Mailgateway\Settings::DEFAULTS, ['host' => 'mail.example.com', 'username' => 'support@example.com', 'mailbox' => 'support@example.com', 'enabled' => true, 'password' => 'TEST-SECRET']);
+$pollStore = new class($enabled) {
+    public function __construct(public $settings) {}
+    public function getAll() { return ['default' => $this->settings, 'disabled' => array_replace($this->settings, ['enabled' => false]), 'other' => array_replace($this->settings, ['mailbox' => 'other@example.com'])]; }
+};
+$pollDi['mailgateway_settings'] = $pollStore;
+$pollService->setDi($pollDi);
+$data = ['mailbox' => $enabled['mailbox'], 'sender_email' => 'guest@example.com', 'subject' => 'New email', 'content' => 'Body'];
+$transport = new class($data) {
+    public array $messages;
+    public array $moves = [];
+    public int $connections = 0;
+    public bool $disconnected = false;
+    public bool $failMove = true;
+    public function __construct($data) {
+        $this->messages = [
+            1 => $data + ['message_id' => '<poll-1@example.com>'],
+            2 => array_replace($data, ['message_id' => '<poll-2@example.com>', 'subject' => 'Re: [Ticket #101] New email']),
+            3 => ['mailbox' => $data['mailbox'], 'message_id' => '<poll-3@example.com>', 'headers' => ['Auto-Submitted' => 'auto-replied']],
+            4 => array_replace($data, ['message_id' => '<poll-4@example.com>', 'subject' => '[Ticket #999] Unknown']),
+            5 => array_replace($data, ['message_id' => '<poll-5@example.com>', 'content' => 'database failure']),
+            6 => new RuntimeException('SECRET fetch failure'),
+        ];
+    }
+    public function connect() { ++$this->connections; }
+    public function uids($limit) { if ($limit !== 50) { throw new RuntimeException('Batch unbounded'); } return array_keys($this->messages); }
+    public function read($uid) { $data = $this->messages[$uid]; if ($data instanceof Throwable) { throw $data; } return $data; }
+    public function move($uid, $destination) {
+        if ($uid === 1 && $this->failMove) { throw new RuntimeException('SECRET move failure'); }
+        $this->moves[$uid] = $destination;
+        unset($this->messages[$uid]);
+    }
+    public function disconnect() { $this->disconnected = true; }
+};
+$other = new class {
+    public bool $disconnected = false;
+    public function connect() { throw new RuntimeException('TEST-SECRET login failure'); }
+    public function disconnect() { $this->disconnected = true; }
+};
+$clock = 10000;
+$locked = false;
+$releases = 0;
+$locker = function ($acquire) use (&$locked, &$releases) {
+    if ($acquire) { if ($locked) { return false; } $locked = true; return true; }
+    $locked = false; ++$releases; return true;
+};
+$factory = fn ($settings) => $settings['mailbox'] === 'other@example.com' ? $other : $transport;
+$poller = new \Box\Mod\Mailgateway\Poller($pollDi, $pollService, $factory, function () use (&$clock) { return $clock; }, $locker);
+$pollDi['mod_service'] = $pollDi->protect(fn ($module) => $module === 'system' ? $system : $pollService);
+$result = $poller->poll();
+$counts = $result['mailboxes']['default'];
+$diagnostics = $counts['errors'];
+unset($counts['errors']);
+if ($diagnostics[0]['stage'] !== 'moving email' || $diagnostics[1]['stage'] !== 'importing email'
+    || $diagnostics[3]['stage'] !== 'reading email'
+    || str_contains(json_encode($diagnostics), 'SECRET')) {
+    throw new RuntimeException('Missing or unsafe poll diagnostics');
+}
+if ($counts !== ['status' => 'completed', 'ticket' => 1, 'reply' => 1, 'ignored' => 1, 'duplicate' => 0, 'failed' => 1, 'retry_pending' => 2, 'move_pending' => 1]
+    || $result['mailboxes']['other']['status'] !== 'failed' || isset($result['mailboxes']['disabled'])
+    || $transport->moves !== [2 => 'processed_folder', 3 => 'ignored_folder', 4 => 'failed_folder']
+    || !$transport->disconnected || !$other->disconnected || $locked) {
+    throw new RuntimeException('Polling result or folder routing incorrect: ' . json_encode($result));
+}
+$clock += 299;
+if ($poller->poll()['status'] !== 'not_due' || $transport->connections !== 1 || $locked) { throw new RuntimeException('Five-minute interval failed'); }
+$clock++;
+$transport->failMove = false;
+$result = $poller->poll();
+if ($result['mailboxes']['default']['duplicate'] !== 1 || $transport->moves[1] !== 'processed_folder'
+    || (int) $pollDb->fetchOne('SELECT COUNT(*) FROM imported') !== 2) { throw new RuntimeException('Move retry duplicated import'); }
+if ($poller->poll(true)['status'] !== 'completed') { throw new RuntimeException('Forced run failed'); }
+$locked = true;
+if ($poller->poll(true)['status'] !== 'busy') { throw new RuntimeException('Concurrent poll allowed'); }
+$locked = false;
+$pollStore->settings['enabled'] = false;
+if ($poller->poll()['status'] !== 'disabled' || $locked) { throw new RuntimeException('Disabled mailbox handling failed'); }
+if (str_contains(implode("\n", $pollDi['logger']->logs), 'SECRET')) { throw new RuntimeException('Polling leaked secrets'); }
+
+// Use the installed MIME parser offline: real encoded headers, multipart and HTML.
+$config = \Webklex\PHPIMAP\Config::make(['options' => ['debug' => false]]);
+$raw = "From: =?UTF-8?B?U2Vi?= <seb@molenaar.co.uk>\r\nTo: support@example.com\r\nMessage-ID: <mime-1@example.com>\r\nSubject: =?UTF-8?B?VGVzdCDDqQ==?=\r\nMIME-Version: 1.0\r\nContent-Type: multipart/alternative; boundary=boundary\r\n\r\n--boundary\r\nContent-Type: text/plain; charset=UTF-8\r\nContent-Transfer-Encoding: quoted-printable\r\n\r\nPlain =C3=A9\r\n--boundary\r\nContent-Type: text/html; charset=UTF-8\r\n\r\n<p>HTML</p>\r\n--boundary--\r\n";
+$message = \Webklex\PHPIMAP\Message::fromString($raw, $config);
+$headers = \Box\Mod\Mailgateway\ImapMailbox::rawHeaders($message->getHeader()->raw);
+$parsed = \Box\Mod\Mailgateway\ImapMailbox::data($message, 'support@example.com', $headers, false);
+if ($parsed['sender_email'] !== 'seb@molenaar.co.uk' || $parsed['sender_name'] !== 'Seb'
+    || $parsed['subject'] !== 'Test é' || $parsed['content'] !== 'Plain é' || $parsed['message_id'] !== '<mime-1@example.com>') { throw new RuntimeException('Real MIME decode failed: ' . json_encode($parsed)); }
+$rawHtml = "From: Seb <seb@molenaar.co.uk>\r\nContent-Type: text/html; charset=UTF-8\r\n\r\n<style>SECRET STYLE</style><script>SECRET SCRIPT</script><p>Hello &amp; welcome</p><p>Second line</p>";
+$message = \Webklex\PHPIMAP\Message::fromString($rawHtml, $config);
+$headers = \Box\Mod\Mailgateway\ImapMailbox::rawHeaders($message->getHeader()->raw);
+$parsed = \Box\Mod\Mailgateway\ImapMailbox::data($message, 'support@example.com', $headers, false);
+$again = \Box\Mod\Mailgateway\ImapMailbox::data($message, 'support@example.com', $headers, false);
+if ($parsed['content'] !== "Hello & welcome\nSecond line" || $parsed['subject'] !== '(No subject)' || $parsed['message_id'] !== $again['message_id']) { throw new RuntimeException('HTML fallback or missing-ID fingerprint failed'); }
+$headers = \Box\Mod\Mailgateway\ImapMailbox::rawHeaders("Return-Path: <>\r\nAuto-Submitted: no\r\nAuto-Submitted: auto-replied;\r\n reason=vacation\r\n");
+$policy = new \Box\Mod\Mailgateway\InboundPolicy();
+if (count($headers['auto-submitted']) !== 2 || $headers['return-path'] !== ['<>'] || $policy->ignoreReason($policy->headers(['headers' => $headers])) === null) { throw new RuntimeException('Raw automatic headers lost'); }
+
+$event = new \Box_Event(null, 'onBeforeAdminCronRun');
+$hookDi = new \Pimple\Container();
+$hookDi['logger'] = $pollDi['logger'];
+$hookDi['mod_service'] = $hookDi->protect(fn ($module) => new class { public function poll() { throw new RuntimeException('SECRET'); } });
+$event->setDi($hookDi);
+\Box\Mod\Mailgateway\Service::onBeforeAdminCronRun($event);
+echo "Passed cron isolation, five-minute cadence, overlap lock, disabled mailboxes, folder routing, failure retry, move-failure deduplication, real MIME/HTML parsing, stable missing-ID tracking, raw autoresponder headers, and secret-safe logs.\n";
+
+// Exercise the real transport orchestration without opening a network connection.
+$imapBody = "Hello from the inbox.";
+$imapHeader = "From: Seb <seb@molenaar.co.uk>\r\nMessage-ID: <transport@example.com>\r\nSubject: Inbox test\r\nContent-Type: text/plain; charset=UTF-8\r\n";
+$transportMessage = new class($imapHeader, $config) {
+    public $message;
+    public string $body = '';
+    public function __construct(public string $raw, public $config) { $this->parseRawBody(''); }
+    public function parseRawBody($body) { $this->body = $body; $this->message = \Webklex\PHPIMAP\Message::fromString($this->raw . "\r\n" . $body, $this->config); }
+    public function getHeader() { return $this->message->getHeader(); }
+    public function getFrom() { return $this->message->getFrom(); }
+    public function getSubject() { return $this->message->getSubject(); }
+    public function getTextBody() { return $this->message->getTextBody(); }
+    public function getHTMLBody() { return $this->message->getHTMLBody(); }
+    public function getRawBody() { return $this->body; }
+    public function getSize() { return 1000; }
+};
+$query = new class($transportMessage) {
+    public bool $peek = false;
+    public bool $undeleted = false;
+    public function __construct(public $message) {}
+    public function leaveUnread() { $this->peek = true; return $this; }
+    public function setSequence($value) { if ($value !== \Webklex\PHPIMAP\IMAP::ST_UID) { throw new RuntimeException('Expected UID search'); } return $this; }
+    public function whereUndeleted() { $this->undeleted = true; return $this; }
+    public function search() { return new \Illuminate\Support\Collection([39, 37, 38]); }
+    public function fetchBody($value) { if ($value !== false) { throw new RuntimeException('Body fetched before size/policy checks'); } return $this; }
+    public function setFetchFlags($value) { return $this; }
+    public function getMessageByUid($uid) { if ($uid !== 37 || !$this->peek) { throw new RuntimeException('Unsafe message fetch'); } return $this->message; }
+};
+$protocol = new class($imapBody) {
+    public array $commands = [];
+    public bool $supportsMove = true;
+    public function __construct(public string $body) {}
+    public function getCapabilities() { return new class($this->supportsMove) { public function __construct(public bool $move) {} public function validatedData() { return $this->move ? ['IMAP4rev1', 'MOVE'] : ['IMAP4rev1']; } }; }
+    public function fetch($items, $uids, $to, $sequence) {
+        if ($items !== ['BODY.PEEK[TEXT]', 'UID'] || $uids !== [37] || $sequence !== \Webklex\PHPIMAP\IMAP::ST_UID) { throw new RuntimeException('Unsafe body fetch'); }
+        $this->commands[] = 'BODY.PEEK[TEXT]';
+        return new class($this->body) { public function __construct(public string $body) {} public function validatedData() { return [37 => ['UID' => 37, 'BODY[TEXT]' => $this->body]]; } };
+    }
+    public function escapeString($path) { return '"' . $path . '"'; }
+    public function requestAndResponse($command, $tokens, $dontParse) {
+        if ($command !== 'UID MOVE' || $tokens !== ['37', '"Processed"'] || !$dontParse) { throw new RuntimeException('Unsafe move or expunge'); }
+        $this->commands[] = $command;
+        return new class { public function boolean() { return true; } };
+    }
+};
+$client = new class($protocol, $query) {
+    public bool $disconnected = false;
+    public function __construct(public $protocol, public $query) {}
+    public function connect() {}
+    public function disconnect() { $this->disconnected = true; }
+    public function getConnection() { return $this->protocol; }
+    public function getFolderByPath($path) { return new class($path, $this->query) { public bool $no_select = false; public function __construct(public string $path, public $q) {} public function query() { return $this->q; } }; }
+    public function openFolder($path) { if ($path !== 'INBOX') { throw new RuntimeException('Move from wrong inbox'); } }
+};
+$imap = new \Box\Mod\Mailgateway\ImapMailbox($enabled, function ($config) use ($client) {
+    if (!$config['validate_cert'] || $config['password'] !== 'TEST-SECRET' || $config['timeout'] !== 15) { throw new RuntimeException('Unsafe client config'); }
+    return $client;
+});
+$imap->connect();
+if ($imap->uids(2) !== [37, 38] || !$query->undeleted) { throw new RuntimeException('UID ordering or undeleted filtering failed'); }
+$transportData = $imap->read(37);
+if ($transportData['content'] !== $imapBody || $transportData['message_id'] !== '<transport@example.com>') { throw new RuntimeException('Transport MIME conversion failed'); }
+$imap->move(37, 'processed_folder');
+$imap->disconnect();
+if (!$client->disconnected || $protocol->commands !== ['BODY.PEEK[TEXT]', 'UID MOVE']) { throw new RuntimeException('Unsafe transport side effects'); }
+$protocol->supportsMove = false;
+try { $imap->connect(); throw new RuntimeException('Unsafe MOVE fallback enabled'); } catch (\FOSSBilling\InformationException) {} finally { $imap->disconnect(); }
+echo "Passed transport configuration, UID snapshot order, deleted-mail exclusion, true BODY.PEEK reads, native UID MOVE, and rejection of servers requiring an EXPUNGE fallback.\n";
+
+// Verify option setters against the installed API, rather than only a transport mock.
+$offlineClient = (new \Webklex\PHPIMAP\ClientManager(['options' => ['debug' => false]]))->make([
+    'host' => 'example.invalid', 'port' => 993, 'protocol' => 'imap',
+    'encryption' => 'ssl', 'validate_cert' => true,
+    'username' => 'offline@example.invalid', 'password' => 'test-only',
+]);
+$realQuery = new \Webklex\PHPIMAP\Query\WhereQuery($offlineClient);
+$realQuery->leaveUnread()->fetchBody(false)->setFetchFlags(false);
+if ($realQuery->getFetchBody() || $realQuery->getFetchFlags()
+    || $realQuery->getFetchOptions() !== \Webklex\PHPIMAP\IMAP::FT_PEEK) {
+    throw new RuntimeException('Installed IMAP query options differ from importer assumptions');
+}
+echo "Passed installed WhereQuery option setters without connecting to IMAP.\n";
+
+// Validate SSH configuration overrides and reject invalid storage limits.
+$runtime = require dirname(__DIR__) . '/config.php';
+$fixture = tempnam(sys_get_temp_dir(), 'mailgateway-runtime-');
+try {
+    $changed = array_replace($runtime, ['poll_interval_seconds' => 600, 'messages_per_mailbox' => 10,
+        'imap_timeout_seconds' => 25, 'max_ticket_body_bytes' => 32000]);
+    file_put_contents($fixture, '<?php return ' . var_export($changed, true) . ';');
+    if (\Box\Mod\Mailgateway\RuntimeConfig::load($fixture) !== $changed) {
+        throw new RuntimeException('SSH operational overrides not loaded');
+    }
+    foreach ([['poll_interval_seconds' => 0], ['max_ticket_body_bytes' => 65536],
+        ['messages_per_mailbox' => '50'], ['composer_paths' => ['relative/composer']]] as $invalid) {
+        file_put_contents($fixture, '<?php return ' . var_export(array_replace($runtime, $invalid), true) . ';');
+        $rejected = false;
+        try { \Box\Mod\Mailgateway\RuntimeConfig::load($fixture); } catch (RuntimeException) { $rejected = true; }
+        if (!$rejected) { throw new RuntimeException('Invalid SSH operational config accepted'); }
+    }
+} finally {
+    unlink($fixture);
+}
+echo "Passed blank mailbox defaults, saved mailbox preservation, SSH configuration overrides, and operational value validation.\n";
+
+// Activation creates tables before attempting dependencies and permits recovery
+// through the settings page when Composer is unavailable.
+foreach ([false, true] as $failDependencies) {
+    $setupDb = new class {
+        public array $statements = [];
+        public function executeStatement($sql) { $this->statements[] = $sql; }
+    };
+    $setupLogger = new class {
+        public array $warnings = [];
+        public function warning($message) { $this->warnings[] = $message; }
+    };
+    $setupDi = new \Pimple\Container();
+    $setupDi['dbal'] = $setupDb;
+    $setupDi['logger'] = $setupLogger;
+    $setupDi['mailgateway_template_installer'] = new class { public function install() {} };
+    $setupService = new class($setupDb, $failDependencies) extends \Box\Mod\Mailgateway\Service {
+        public int $installs = 0;
+        public function __construct(public $db, public bool $fail) {}
+        public function installDependencies(bool $force = false): array {
+            ++$this->installs;
+            if (count($this->db->statements) !== 3) { throw new LogicException('Dependencies attempted before table setup'); }
+            if ($this->fail) { throw new RuntimeException('SECRET Composer failure'); }
+            return ['installed' => true];
+        }
+    };
+    $setupService->setDi($setupDi);
+    if (!$setupService->install() || $setupService->installs !== 1 || count($setupDb->statements) !== 3
+        || count($setupLogger->warnings) !== ($failDependencies ? 1 : 0)
+        || str_contains(implode(' ', $setupLogger->warnings), 'SECRET')) {
+        throw new RuntimeException('Activation dependency setup or recoverable failure handling failed');
+    }
+}
+echo "Passed activation table setup, automatic dependency install attempt, and recoverable installation failures without running Composer.\n";
+
+$repairDb = new class {
+    public array $statements = [];
+    public array $locks = [];
+    public bool $busy = false;
+    public function fetchOne($sql, $params) { $this->locks[] = $sql; return str_contains($sql, 'GET_LOCK') && $this->busy ? 0 : 1; }
+    public function executeStatement($sql) {
+        if (!str_starts_with(trim($sql), 'CREATE TABLE IF NOT EXISTS')) { throw new RuntimeException('Unexpected table repair SQL'); }
+        $this->statements[] = $sql;
+    }
+};
+$repairDi = new \Pimple\Container();
+$repairDi['dbal'] = $repairDb;
+$repairDi['mailgateway_template_installer'] = new class { public function install() {} };
+$repairService = new class extends \Box\Mod\Mailgateway\Service {
+    public function installDependencies(bool $force = false): array { throw new RuntimeException('Table repair must not invoke Composer'); }
+};
+$repairService->setDi($repairDi);
+$repairService->setup();
+$repairService->setup();
+if (count($repairDb->statements) !== 6 || count($repairDb->locks) !== 4
+    || !str_contains($repairDb->locks[3], 'RELEASE_LOCK')) { throw new RuntimeException('Repeatable table repair or overlap lock failed'); }
+$repairDb->busy = true;
+try { $repairService->setup(); throw new RuntimeException('Repair allowed while polling'); } catch (\FOSSBilling\InformationException) {}
+echo "Passed repeatable table setup, shared polling lock, and separate setup/Composer actions.\n";
+
+require dirname(__DIR__) . '/TemplateInstaller.php';
+$templateDi = new \Pimple\Container();
+$templateEmail = new class {
+    public array $templates = [];
+    public int $creates = 0;
+    public function getTemplateRepository() { return $this; }
+    public function findOneByActionCode($code) { return $this->templates[$code] ?? null; }
+    public function templateCreate($code, $subject, $content, $enabled, $category) {
+        ++$this->creates;
+        return $this->templates[$code] = (new \Box\Mod\Email\Entity\EmailTemplate($code))
+            ->setSubject($subject)->setContent($content)->setEnabled((bool) $enabled)->setCategory($category)->setIsCustom(true);
+    }
+};
+$templateDi['mod_service'] = $templateDi->protect(fn ($module) => $templateEmail);
+$templateInstaller = new \Box\Mod\Mailgateway\TemplateInstaller($templateDi);
+$templateInstaller->install();
+$templateInstaller->install();
+$template = $templateEmail->templates['mailgateway_sender_mismatch'];
+if ($templateEmail->creates !== 1 || !$template->isEnabled() || $template->getCategory() !== 'mailgateway') {
+    throw new RuntimeException('Fresh mismatch template was not installed exactly once');
+}
+$templateTwig = new \Twig\Environment(new \Twig\Loader\ArrayLoader(), ['autoescape' => 'html', 'strict_variables' => true]);
+$templateGlobals = ['guest' => ['system_company' => ['name' => 'Example Company'],
+    'system_email' => ['signature' => 'Example signature']]];
+$subject = $templateTwig->createTemplate($template->getSubject())->render($templateGlobals);
+$body = $templateTwig->createTemplate($template->getContent())->render($templateGlobals);
+if ($subject !== '[Example Company] Unable to process your support reply'
+    || !str_contains($body, 'Thank you for contacting Example Company.')
+    || !str_contains($body, 'Example signature')
+    || !str_contains($body, 'Your message has not been added to the ticket.')) {
+    throw new RuntimeException('Packaged mismatch template did not render the supplied wording with normal globals');
+}
+$template->setSubject('My custom subject')->setContent('My custom content')->setEnabled(false);
+$templateInstaller->install();
+if ($templateEmail->creates !== 1 || $template->getSubject() !== 'My custom subject'
+    || $template->getContent() !== 'My custom content' || $template->isEnabled()) {
+    throw new RuntimeException('Existing mismatch template content or disabled setting was overwritten');
+}
+echo "Passed fresh mismatch-template installation, repeatability, Twig rendering with minimal variables, and preservation of custom content/disabled state.\n";
diff --git a/tests/replies.php b/tests/replies.php
new file mode 100644
index 0000000..1b66f7f
--- /dev/null
+++ b/tests/replies.php
@@ -0,0 +1,152 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/validation.php';
+
+use Box\Mod\Support\Entity\Helpdesk;
+use Box\Mod\Support\Entity\SupportTicket;
+use Box\Mod\Support\Entity\SupportTicketMessage;
+
+$ticket = new SupportTicket();
+(new ReflectionProperty($ticket, 'id'))->setValue($ticket, 4);
+$ticket->setClientId(7);
+$ticket->setStatus('on_hold');
+$helpdesk = new Helpdesk();
+$helpdesk->setCanReopen(true);
+$ticket->setSupportHelpdesk($helpdesk);
+$support = new class($ticket) extends \Box\Mod\Support\Service {
+    public function __construct(private SupportTicket $ticket) {}
+    public function setDi(\Pimple\Container $di): void { $this->di = $di; }
+    public function getTicketById(int $id): SupportTicket
+    {
+        if ($id !== 4) {
+            throw new \FOSSBilling\InformationException('Ticket not found');
+        }
+        return $this->ticket;
+    }
+};
+$em = new class {
+    public array $messages = [];
+    public function persist($message): void
+    {
+        if (!$message instanceof SupportTicketMessage) {
+            throw new RuntimeException('Unexpected entity');
+        }
+        (new ReflectionProperty($message, 'id'))->setValue($message, count($this->messages) + 10);
+        $this->messages[] = $message;
+    }
+    public function flush(): void {}
+};
+$di = new \Pimple\Container();
+$lookup = new class {
+    public array $ids = [7];
+    public function fetchFirstColumn($sql, $params) { return $this->ids; }
+};
+$di['dbal'] = $lookup;
+$di['mailgateway_notification_cooldown'] = new class {
+    public function run($sender, $queue): bool { return $queue() !== false; }
+};
+$di['db'] = new class($client) {
+    public function __construct(public $client) {}
+    public function getExistingModelById($type, $id) { return $this->client; }
+};
+$di['em'] = $em;
+$di['request'] = new \Symfony\Component\HttpFoundation\Request();
+$di['events_manager'] = new class {
+    public array $events = [];
+    public function fire($data): void { $this->events[] = $data; }
+};
+$di['logger'] = new class {
+    public function info(...$args): void {}
+    public function warning(...$args): void {}
+};
+$email = new class {
+    public array $notifications = [];
+    public bool $fail = false;
+    public function sendTemplate($data): void
+    {
+        if ($this->fail) {
+            throw new RuntimeException('Simulated mail failure');
+        }
+        $this->notifications[] = $data;
+    }
+};
+$di['mod_service'] = $di->protect(fn ($module) => $module === 'email' ? $email : $support);
+$support->setDi($di);
+$service->setDi($di);
+$reply = ['ticket_id' => '4', 'sender_email' => 'customer@example.com', 'content' => ' Customer reply '];
+$result = $service->reply($reply);
+if ($result !== ['ticket_id' => 4, 'message_id' => 10]
+    || $ticket->getStatus() !== 'open' || $em->messages[0]->getClientId() !== 7
+    || $em->messages[0]->getAdminId() !== null || $em->messages[0]->getContent() !== 'Customer reply') {
+    throw new RuntimeException('Customer reply attribution or status incorrect');
+}
+
+foreach ([[], [8], [7, 8]] as $ids) {
+    $lookup->ids = $ids;
+    try {
+        $service->reply($reply);
+        throw new RuntimeException('Wrong or ambiguous sender accepted');
+    } catch (\FOSSBilling\InformationException) {}
+}
+$lookup->ids = [7];
+foreach ([0, -1, '4x', [], true, null, 4.5, 999] as $id) {
+    try {
+        $service->reply(array_replace($reply, ['ticket_id' => $id]));
+        throw new RuntimeException('Invalid or missing ticket accepted');
+    } catch (\FOSSBilling\InformationException) {}
+}
+$ticket->setStatus('closed');
+$helpdesk->setCanReopen(false);
+try {
+    $service->reply($reply);
+    throw new RuntimeException('Reopen restriction bypassed');
+} catch (\FOSSBilling\InformationException) {}
+$helpdesk->setCanReopen(true);
+$service->reply($reply);
+
+// A guest ticket retains its guest owner even if that address later registers.
+$ticket->setClientId(null);
+$ticket->setAccessHash('private-hash');
+$ticket->setAuthorEmail('guest@example.com');
+$ticket->setStatus('on_hold');
+$reply['sender_email'] = 'GUEST@example.com';
+$service->reply($reply);
+$message = $em->messages[2];
+if ($message->getClientId() !== null || $message->getAdminId() !== null || $ticket->getStatus() !== 'open') {
+    throw new RuntimeException('Guest reply attribution or status incorrect');
+}
+$reply['sender_email'] = 'other@example.com';
+try {
+    $service->reply($reply);
+    throw new RuntimeException('Wrong guest accepted');
+} catch (\FOSSBilling\InformationException) {}
+if (count($em->messages) !== 3) {
+    throw new RuntimeException('Rejected reply created a message');
+}
+if ($email->notifications !== []) {
+    throw new RuntimeException('Direct reply processing attempted a notification');
+}
+$service->notifySenderMismatch('other@example.com', 4);
+foreach ($email->notifications as $notification) {
+    if ($notification !== [
+        'to' => $notification['sender_email'],
+        'code' => 'mailgateway_sender_mismatch',
+        'sender_email' => $notification['sender_email'],
+        'ticket_id' => 4,
+    ]) {
+        throw new RuntimeException('Mismatch notification contains incorrect or private ticket data');
+    }
+}
+$email->fail = true;
+$service->notifySenderMismatch('other@example.com', 4);
+try {
+    $service->reply($reply);
+    throw new RuntimeException('Mail failure allowed a mismatched reply');
+} catch (\FOSSBilling\InformationException) {}
+if (count($em->messages) !== 3) {
+    throw new RuntimeException('Mail failure created a message');
+}
+echo "Passed customer and guest reply attribution, sender ownership, ambiguity, ticket validation, and reopen policy using Support ticketReply.\n";
+echo "Passed mismatch notification recipient, private data exclusion, and rejection despite mail failure.\n";
diff --git a/tests/settings.php b/tests/settings.php
new file mode 100644
index 0000000..666ad70
--- /dev/null
+++ b/tests/settings.php
@@ -0,0 +1,488 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/cooldown.php';
+$connection->executeStatement('CREATE TABLE mailgateway_settings (id INTEGER PRIMARY KEY, config_encrypted TEXT NOT NULL)');
+$di = new \Pimple\Container();
+$di['dbal'] = $connection;
+$di['crypt'] = new class extends \Box_Crypt {
+    public function encrypt(string $text, ?string $pass = null): string { return parent::encrypt($text, 'isolated-settings-test-key'); }
+    public function decrypt(?string $text, ?string $pass = null) { return parent::decrypt($text, 'isolated-settings-test-key'); }
+};
+$desk = new \Box\Mod\Support\Entity\Helpdesk();
+(new ReflectionProperty($desk, 'id'))->setValue($desk, 2);
+$ticket = new \Box\Mod\Support\Entity\SupportTicket();
+(new ReflectionProperty($ticket, 'id'))->setValue($ticket, 61);
+$support = new class($desk, $ticket) {
+    public array $created = [];
+    public function __construct(public $desk, public $ticket) {}
+    public function getHelpdeskRepository() { return $this; }
+    public function find($id) { return $id === 2 ? $this->desk : null; }
+    public function findBy(...$args) { throw new RuntimeException('Configured helpdesk was ignored'); }
+    public function ticketCreateForGuest($data) { $this->created[] = $data; return 'guest-hash'; }
+    public function findOneByHash($hash) { return $this->ticket; }
+};
+$di['mod_service'] = $di->protect(fn ($module, $sub = '') => $support);
+$store = new \Box\Mod\Mailgateway\Settings($di);
+if ($store->get() !== \Box\Mod\Mailgateway\Settings::DEFAULTS || $store->getPublic()['password_configured']
+    || $store->get()['host'] !== '' || $store->get()['username'] !== '' || $store->get()['mailbox'] !== '') {
+    throw new RuntimeException('Settings defaults incorrect');
+}
+$input = array_replace(\Box\Mod\Mailgateway\Settings::DEFAULTS, [
+    'host' => 'mail.example.com', 'username' => 'support@example.com', 'mailbox' => 'support@example.com',
+    'enabled' => '0', 'support_helpdesk_id' => '2', 'password' => 'test-only-password',
+]);
+$store->save($input);
+$stored = $connection->fetchOne('SELECT config_encrypted FROM mailgateway_settings WHERE id = 1');
+if (!str_starts_with($stored, 'v2:') || str_contains($stored, 'test-only-password')
+    || str_contains($stored, 'support@example.com') || array_key_exists('password', $store->getPublic())) {
+    throw new RuntimeException('Settings stored or exposed in plaintext');
+}
+$input['password'] = '';
+$store->save($input);
+if ($store->get()['password'] !== 'test-only-password' || !$store->getPublic()['password_configured']) {
+    throw new RuntimeException('Blank password did not preserve saved credential');
+}
+foreach ([
+    ['host' => 'https://example.com'], ['port' => '0'], ['port' => '65536'],
+    ['encryption' => 'none'], ['mailbox' => 'bad-email'], ['enabled' => 'maybe'],
+    ['inbox_folder' => 'Processed'], ['username' => "bad\r\nuser"],
+    ['support_helpdesk_id' => '999'], ['password' => ['invalid']],
+    ['clear_password' => '1', 'password' => 'conflicting-password'],
+] as $changes) {
+    try {
+        $store->save(array_replace($input, $changes));
+        throw new RuntimeException('Invalid settings accepted');
+    } catch (\FOSSBilling\InformationException) {}
+}
+$service = new \Box\Mod\Mailgateway\Service();
+$service->setDi($di);
+$result = $service->import(['sender_email' => 'new-guest@example.com', 'subject' => 'Configured helpdesk', 'content' => 'Test body']);
+if ($result['support_helpdesk_id'] !== 2 || $support->created[0]['support_helpdesk_id'] !== 2) {
+    throw new RuntimeException('Selected helpdesk not used for import');
+}
+$input['enabled'] = '0';
+$input['clear_password'] = '1';
+$store->save($input);
+if ($store->getPublic()['password_configured']) { throw new RuntimeException('Password not cleared'); }
+try {
+    $store->save(array_replace($input, ['enabled' => '1', 'clear_password' => '0']));
+    throw new RuntimeException('Enabled imports without a password');
+} catch (\FOSSBilling\InformationException) {}
+
+$input['clear_password'] = '0';
+$input['password'] = 'test-only-password';
+$store->save($input);
+$source = file_get_contents(dirname(__DIR__) . '/templates/admin/mod_mailgateway_settings.html.twig');
+$twig = new \Twig\Environment(new \Twig\Loader\ArrayLoader([
+    'settings' => $source,
+    'layout_default.html.twig' => '{% block content %}{% endblock %}',
+    'layout_blank.html.twig' => '{% block content %}{% endblock %}',
+]), ['autoescape' => 'html', 'strict_variables' => true]);
+$twig->addFilter(new \Twig\TwigFilter('trans', fn ($text) => $text));
+$twig->addFilter(new \Twig\TwigFilter('api_url', fn ($path, $role = 'admin') => '/api/admin/' . $path));
+$twig->addFunction(new \Twig\TwigFunction('fb_api_form', fn ($options) => 'class="api-form"', ['is_safe' => ['html']]));
+$admin = new class($store) {
+    public function __construct(public $store) {}
+    public function mailgateway_settings_get($data) { return ['settings' => $this->store->getPublic(), 'helpdesks' => [2 => 'Helpdesk <script>']]; }
+};
+$html = $twig->render('settings', ['request' => ['ajax' => false], 'admin' => $admin]);
+if (str_contains($html, 'test-only-password') || str_contains($html, 'Helpdesk <script>')
+    || !str_contains($html, 'Helpdesk &lt;script&gt;') || !str_contains($html, '/api/admin/mailgateway/settings_save')) {
+    throw new RuntimeException('Settings page leaked credentials or failed to escape values');
+}
+$api = new \Box\Mod\Mailgateway\Api\Admin();
+foreach (['settings_get', 'settings_save', 'install_dependencies', 'setup', 'mailbox_delete', 'notifications_setup'] as $method) {
+    try {
+        $api->$method([]);
+        throw new RuntimeException('Unauthenticated settings access accepted');
+    } catch (\FOSSBilling\InformationException) {}
+}
+echo "Passed settings validation, actual encryption, secret redaction, password retention/clearing, selected helpdesk routing, Twig rendering/escaping, and unauthenticated rejection.\n";
+
+// Existing single-mailbox ciphertext migrates without losing its credentials.
+$legacy = array_replace(\Box\Mod\Mailgateway\Settings::DEFAULTS, ['host' => 'legacy.example.com', 'username' => 'legacy@example.com', 'mailbox' => 'legacy@example.com', 'password' => 'legacy-password', 'support_helpdesk_id' => 2]);
+$connection->update('mailgateway_settings', ['config_encrypted' => $di['crypt']->encrypt(json_encode($legacy))], ['id' => 1]);
+if ($store->get() !== $legacy) { throw new RuntimeException('Legacy mailbox values or password changed'); }
+$secondDesk = new \Box\Mod\Support\Entity\Helpdesk();
+(new ReflectionProperty($secondDesk, 'id'))->setValue($secondDesk, 3);
+$multiSupport = new class($support, $secondDesk) {
+    public function __construct(public $original, public $secondDesk) {}
+    public function getHelpdeskRepository() { return $this; }
+    public function find($id) { return $id === 3 ? $this->secondDesk : $this->original->find($id); }
+    public function ticketCreateForGuest($data) { return $this->original->ticketCreateForGuest($data); }
+    public function findOneByHash($hash) { return $this->original->findOneByHash($hash); }
+};
+unset($di['mod_service']);
+$di['mod_service'] = $di->protect(fn ($module, $sub = '') => $multiSupport);
+$new = array_replace($input, ['mailbox_id' => 'new', 'mailbox' => 'billing@example.com', 'username' => 'billing@example.com', 'support_helpdesk_id' => 3, 'password' => 'second-password']);
+$store->save($new);
+$mailboxes = $store->getAllPublic();
+$newId = array_key_last($mailboxes);
+if (count($mailboxes) !== 2 || $store->get()['password'] !== 'legacy-password' || $store->get($newId)['password'] !== 'second-password') {
+    throw new RuntimeException('Adding mailbox overwrote credentials');
+}
+$new['mailbox_id'] = $newId;
+$new['password'] = '';
+$store->save($new);
+if ($store->get($newId)['password'] !== 'second-password') { throw new RuntimeException('Wrong mailbox password retained'); }
+try {
+    $store->save(array_replace($new, ['mailbox_id' => 'new']));
+    throw new RuntimeException('Duplicate mailbox accepted');
+} catch (\FOSSBilling\InformationException) {}
+$result = $service->import(['mailbox' => 'BILLING@example.com', 'sender_email' => 'new-guest@example.com', 'subject' => 'Second helpdesk', 'content' => 'Body']);
+if ($result['support_helpdesk_id'] !== 3) { throw new RuntimeException('Second mailbox routing failed'); }
+try {
+    $service->import(['mailbox' => 'unknown@example.com', 'sender_email' => 'new-guest@example.com', 'subject' => 'Unknown mailbox', 'content' => 'Body']);
+    throw new RuntimeException('Unknown mailbox routed to default');
+} catch (\FOSSBilling\InformationException) {}
+$admin = new class($store) {
+    public function __construct(public $store) {}
+    public function mailgateway_settings_get($data) { return ['settings' => $this->store->getPublic(), 'mailboxes' => $this->store->getAllPublic(), 'helpdesks' => [2 => 'General', 3 => 'Billing']]; }
+};
+$html = $twig->render('settings', ['request' => ['ajax' => false], 'admin' => $admin]);
+if (!str_contains($html, 'billing@example.com') || substr_count($html, '>Test Connection and Create Folders</button>') !== 2 || str_contains($html, 'second-password') || str_contains($html, 'legacy-password')) {
+    throw new RuntimeException('Multiple mailbox rendering failed');
+}
+require dirname(__DIR__) . '/ImapConnectionTest.php';
+trait ImapTestCapabilities
+{
+    public bool $supportsMove = true;
+    public bool $failCapabilities = false;
+    public function getConnection() {
+        return new class($this) {
+            public function __construct(public $client) {}
+            public function getCapabilities() {
+                if ($this->client->failCapabilities) { throw new RuntimeException('SECRET capabilities'); }
+                return new class($this->client->supportsMove) {
+                    public function __construct(public bool $move) {}
+                    public function validatedData() { return $this->move ? ['IMAP4rev1', 'MOVE'] : ['IMAP4rev1']; }
+                };
+            }
+        };
+    }
+}
+$client = new class {
+    use ImapTestCapabilities;
+    public bool $disconnected = false;
+    public bool $fail = false;
+    public function connect() { if ($this->fail) { throw new RuntimeException('secret-second-password'); } }
+    public function getFolders($hierarchical) {
+        if ($hierarchical !== false) { throw new RuntimeException('Expected flat folder listing'); }
+        return [(object) ['path' => 'inbox'], (object) ['path' => 'Processed']];
+    }
+    public function disconnect() { $this->disconnected = true; }
+};
+$test = new \Box\Mod\Mailgateway\ImapConnectionTest(function ($config) use ($client) {
+    if (!$config['validate_cert'] || $config['password'] !== 'second-password' || $config['username'] !== 'billing@example.com') { throw new RuntimeException('Wrong IMAP config'); }
+    return $client;
+});
+$check = $test->test($store->get($newId));
+if (!$check['connected'] || !$check['folders'][0]['exists'] || $check['folders'][2]['exists'] || !$client->disconnected) { throw new RuntimeException('IMAP folder test failed'); }
+$client->fail = true;
+$client->disconnected = false;
+$failedCheck = $test->test($store->get($newId));
+if ($failedCheck['success'] || $failedCheck['connected'] || !$client->disconnected
+    || str_contains(json_encode($failedCheck), 'secret')) {
+    throw new RuntimeException('IMAP failure leaked secrets or skipped cleanup');
+}
+try { $api->test_connection([]); throw new RuntimeException('Unauthenticated IMAP test accepted'); } catch (\FOSSBilling\InformationException) {}
+echo "Passed legacy migration, multiple mailbox credential isolation, duplicate rejection, per-mailbox helpdesk routing, multi-mailbox Twig rendering, read-only IMAP checks, disconnect cleanup, and secret-safe failures.\n";
+
+// Render all dependency states using the actual settings-page template.
+foreach ([
+    [['installed' => true, 'available' => true], 'Mail Gateway dependencies are installed.', true],
+    [['installed' => false, 'available' => true], 'Install dependencies', true],
+    [['installed' => false, 'available' => false], 'Automatic installation is unavailable', false],
+] as [$dependencies, $expected, $button]) {
+    $admin = new class($store, $dependencies) {
+        public function __construct(public $store, public $dependencies) {}
+        public function mailgateway_settings_get($data) {
+            return ['settings' => $this->store->getPublic(), 'mailboxes' => $this->store->getAllPublic(),
+                'helpdesks' => [2 => 'General', 3 => 'Billing'], 'dependencies' => $this->dependencies];
+        }
+    };
+    $html = $twig->render('settings', ['request' => ['ajax' => false], 'admin' => $admin]);
+    if (!str_contains($html, $expected) || str_contains($html, '/api/admin/mailgateway/install_dependencies') !== $button) {
+        throw new RuntimeException('Dependency installation controls rendered incorrectly');
+    }
+    preg_match('/<input[^>]*type="checkbox"[^>]*name="enabled"[^>]*>/', $html, $switch);
+    if ($switch === [] || !str_contains($switch[0], 'disabled')) {
+        throw new RuntimeException('Import switch is not gated by installed dependencies');
+    }
+    if ($dependencies['installed'] && strpos($html, 'Mail Gateway dependencies are installed.') < strpos($html, '>Advanced</summary>')) {
+        throw new RuntimeException('Installed dependency status is outside Advanced');
+    }
+}
+require_once dirname(__DIR__) . '/DependencyInstaller.php';
+$runner = new class extends \Box\Mod\Mailgateway\DependencyInstaller {
+    public function executeForTest(array $command): array { return $this->run($command); }
+};
+$result = $runner->executeForTest([PHP_BINARY, '-r', 'fwrite(STDOUT, str_repeat("secret", 30000)); fwrite(STDERR, str_repeat("secret", 30000)); exit(7);']);
+if ($result !== ['exit' => 7, 'timeout' => false]) {
+    throw new RuntimeException('Dependency runner failed to drain pipes, preserve exit code or suppress sensitive output');
+}
+echo "Passed dependency controls, installer authentication, subprocess pipe draining, exit-code handling, and output redaction without running Composer.\n";
+
+$reinstaller = new class extends \Box\Mod\Mailgateway\DependencyInstaller {
+    public array $commands = [];
+    protected function run(array $command): array {
+        $this->commands[] = $command;
+        return ['exit' => 0, 'timeout' => false];
+    }
+};
+$reinstaller->install();
+if ($reinstaller->commands !== []) { throw new RuntimeException('Normal install did not skip existing dependencies'); }
+$reinstaller->install(true);
+if (count($reinstaller->commands) !== 1 || !in_array('install', $reinstaller->commands[0], true)
+    || !in_array('--no-scripts', $reinstaller->commands[0], true) || !in_array('--no-plugins', $reinstaller->commands[0], true)) {
+    throw new RuntimeException('Forced Composer rerun did not reach the installer');
+}
+if (!str_contains($html, '>Advanced</summary>') || !str_contains($html, '/api/admin/mailgateway/setup')) {
+    throw new RuntimeException('Advanced table setup control missing');
+}
+$missingDb = \Doctrine\DBAL\DriverManager::getConnection(['driver' => 'pdo_sqlite', 'memory' => true]);
+$missingDi = new \Pimple\Container();
+$missingDi['dbal'] = $missingDb;
+if ((new \Box\Mod\Mailgateway\Settings($missingDi))->get()['host'] !== '') {
+    throw new RuntimeException('Missing settings table prevented access to setup page');
+}
+echo "Passed Advanced rendering, forced Composer rerun, and settings recovery when module tables are missing.\n";
+
+$di['mailgateway_dependency_installer'] = new class {
+    public function status() { return ['installed' => false]; }
+};
+try {
+    $store->save(array_replace($new, ['enabled' => '1']));
+    throw new RuntimeException('Importing enabled without installed dependencies');
+} catch (\FOSSBilling\InformationException) {}
+$store->save(array_replace($new, ['enabled' => '0']));
+unset($di['mailgateway_dependency_installer']);
+
+$folderClient = new class {
+    use ImapTestCapabilities;
+    public array $paths = ['Processed'];
+    public array $created = [];
+    public bool $disconnected = false;
+    public bool $failCreate = false;
+    public function connect() {}
+    public function getFolders($hierarchical) { return array_map(fn ($path) => (object) ['path' => $path], $this->paths); }
+    public function createFolder($path, $expunge) {
+        if ($expunge !== false || $path === 'INBOX') { throw new RuntimeException('Unsafe folder creation'); }
+        if ($this->failCreate) { throw new RuntimeException('SECRET folder failure'); }
+        $this->created[] = $path;
+        $this->paths[] = $path;
+    }
+    public function disconnect() { $this->disconnected = true; }
+};
+$folderTest = new \Box\Mod\Mailgateway\ImapConnectionTest(fn ($config) => $folderClient);
+$check = $folderTest->test($store->get($newId), true);
+if ($folderClient->created !== ['Ignored', 'Failed'] || $check['folders'][0]['exists']
+    || !$check['folders'][2]['created'] || !$check['folders'][3]['exists'] || !$folderClient->disconnected) {
+    throw new RuntimeException('Destination folder creation or missing-inbox handling failed');
+}
+$folderTest->test($store->get($newId), true);
+if ($folderClient->created !== ['Ignored', 'Failed']) { throw new RuntimeException('Existing folders were recreated'); }
+$folderClient->paths = [];
+$folderClient->failCreate = true;
+$folderClient->disconnected = false;
+$folderFailure = $folderTest->test($store->get($newId), true);
+if ($folderFailure['success'] || !$folderFailure['connected'] || !$folderClient->disconnected
+    || str_contains(json_encode($folderFailure), 'SECRET')
+    || !str_contains($folderFailure['folders'][1]['error'], 'Folder creation failed')) {
+    throw new RuntimeException('Folder failure did not distinguish login from folder creation');
+}
+echo "Passed dependency status placement, disabled import switches, server-side enablement guard, safe destination folder creation, repeated setup, and failure cleanup.\n";
+
+// Readiness is per mailbox, persisted, and tied to the tested configuration.
+$readyClient = new class {
+    use ImapTestCapabilities;
+    public function connect() {}
+    public function getFolders($hierarchical) { return array_map(fn ($path) => (object) ['path' => $path], ['INBOX', 'Processed', 'Ignored', 'Failed']); }
+    public function disconnect() {}
+};
+$readyTest = new \Box\Mod\Mailgateway\ImapConnectionTest(fn ($config) => $readyClient);
+$readySettings = $store->get($newId);
+$readyResult = $readyTest->test($readySettings, true);
+if (!$readyResult['success']) { throw new RuntimeException('Valid mailbox did not pass readiness'); }
+$store->recordTest($newId, $readySettings, $readyResult);
+if (!$store->getAllPublic()[$newId]['test_passed'] || $store->getPublic()['test_passed']) {
+    throw new RuntimeException('Readiness did not remain isolated to tested mailbox');
+}
+$store->save(array_replace($new, ['enabled' => '1']));
+if (!$store->get($newId)['enabled']) { throw new RuntimeException('Tested mailbox could not be enabled'); }
+$store->save(array_replace($new, ['enabled' => '1', 'host' => 'new-host.example.com']));
+if ($store->get($newId)['enabled'] || $store->getAllPublic()[$newId]['test_passed']) {
+    throw new RuntimeException('Connection changes did not revoke readiness and disable imports');
+}
+try { $store->recordTest($newId, $readySettings, $readyResult); throw new RuntimeException('Stale test accepted'); }
+catch (\FOSSBilling\InformationException) {}
+$readySettings = $store->get($newId);
+$store->recordTest($newId, $readySettings, $readyResult);
+$store->save(array_replace($new, ['enabled' => '1', 'host' => 'new-host.example.com']));
+$store->recordTest($newId, $store->get($newId), $folderFailure);
+if ($store->get($newId)['enabled'] || $store->getAllPublic()[$newId]['test_passed']
+    || $store->getAllPublic()[$newId]['test_result'] !== $folderFailure) {
+    throw new RuntimeException('Failed retest did not disable importing and persist diagnostics');
+}
+try {
+    $store->save(array_replace($new, ['enabled' => '1', 'host' => 'new-host.example.com', 'tested_config_hash' => 'fake', 'test_passed' => true]));
+    throw new RuntimeException('Unverified enablement or spoofed readiness accepted');
+} catch (\FOSSBilling\InformationException) {}
+$sourceSettings = $store->get($newId);
+$di['mailgateway_connection_test'] = $readyTest;
+$service->testConnection(['mailbox_id' => $newId]);
+if (!(new \Box\Mod\Mailgateway\Settings($di))->getAllPublic()[$newId]['test_passed']) {
+    throw new RuntimeException('Settings-page connection test did not persist readiness');
+}
+unset($di['mailgateway_connection_test']);
+$di['mailgateway_connection_test'] = new class($folderFailure) {
+    public function __construct(public $result) {}
+    public function test($settings, $create) { return $this->result; }
+};
+$service->testConnection(['mailbox_id' => $newId]);
+$admin = new class($store) {
+    public function __construct(public $store) {}
+    public function mailgateway_settings_get($data) {
+        return ['settings' => $this->store->getPublic(), 'mailboxes' => $this->store->getAllPublic(),
+            'dependencies' => ['installed' => true, 'available' => true], 'helpdesks' => [2 => 'General', 3 => 'Billing']];
+    }
+};
+$html = $twig->render('settings', ['request' => ['ajax' => false], 'admin' => $admin]);
+if (!str_contains($html, 'Folder creation failed') || !str_contains($html, 'Importing remains disabled')
+    || !str_contains($html, 'title="Save this mailbox, then run Test Connection')) {
+    throw new RuntimeException('Persisted failure or hover explanation missing from page');
+}
+echo "Passed per-mailbox readiness, server-side enablement enforcement, configuration invalidation, stale-test rejection, failed-retest disabling, persisted test results, and explanatory UI.\n";
+
+$keptMailbox = $store->get('default');
+$store->delete($newId);
+if (count($store->getAll()) !== 1 || $store->get('default') !== $keptMailbox) {
+    throw new RuntimeException('Deleting a mailbox modified another mailbox');
+}
+try { $store->delete('unknown'); throw new RuntimeException('Unknown mailbox deletion accepted'); }
+catch (\FOSSBilling\InformationException) {}
+$store->delete('default');
+if ($store->getAll() !== [] || $store->getPublic()['mailbox'] !== '') {
+    throw new RuntimeException('Deleting last mailbox failed');
+}
+$html = $twig->render('settings', ['request' => ['ajax' => false], 'admin' => $admin]);
+if (str_contains($html, '>Delete mailbox</button>') || !str_contains($html, 'Add mailbox')) {
+    throw new RuntimeException('Empty mailbox list rendered a phantom mailbox');
+}
+$new['mailbox_id'] = 'new';
+$new['enabled'] = '0';
+$new['password'] = 'replacement-password';
+$store->save($new);
+if (count($store->getAll()) !== 1 || $store->get()['password'] !== 'replacement-password') {
+    throw new RuntimeException('Adding mailbox after deleting last mailbox failed');
+}
+echo "Passed mailbox deletion, remaining credential preservation, unknown-ID rejection, empty-page rendering, and adding a replacement mailbox.\n";
+
+$readyClient->supportsMove = false;
+$noMove = $readyTest->test($sourceSettings, true);
+if (!$noMove['connected'] || $noMove['success'] || $noMove['move_supported'] !== false
+    || !str_contains(implode(' ', $noMove['errors']), 'does not support native MOVE')) {
+    throw new RuntimeException('Successful login without MOVE was not rejected clearly');
+}
+$readyClient->supportsMove = true;
+$readyClient->failCapabilities = true;
+$capabilityFailure = $readyTest->test($sourceSettings, true);
+if (!$capabilityFailure['connected'] || $capabilityFailure['success']
+    || !str_contains(implode(' ', $capabilityFailure['errors']), 'checking server MOVE support failed')
+    || str_contains(json_encode($capabilityFailure), 'SECRET')) {
+    throw new RuntimeException('MOVE check failure did not preserve login result or hide secrets');
+}
+$readyClient->failCapabilities = false;
+echo "Passed native MOVE requirement, distinct capability failures, and secret-safe shared connection diagnostics.\n";
+
+$notificationDi = new \Pimple\Container();
+$notificationEmail = new class {
+    public array $templates = [];
+    public function getTemplateRepository() { return $this; }
+    public function findOneByActionCode($code) { return $this->templates[$code] ?? null; }
+    public function templateToApiArray($template) {
+        return ['enabled' => $template->isEnabled(), 'subject' => $template->getSubject()];
+    }
+    public int $updates = 0;
+    public function updateTemplate($template, $enabled = null, $category = null, $subject = null): bool {
+        if ($enabled !== null) $template->setEnabled($enabled);
+        if ($subject !== null) $template->setSubject($subject);
+        ++$this->updates;
+        return true;
+    }
+    public function templateCreate($code, $subject, $content, $enabled, $category) {
+        return $this->templates[$code] = (new \Box\Mod\Email\Entity\EmailTemplate($code))
+            ->setSubject($subject)->setContent($content)->setEnabled((bool) $enabled);
+    }
+};
+foreach (['mod_support_ticket_open', 'mod_support_ticket_staff_reply',
+    'mod_support_ticket_staff_open', 'mod_support_ticket_staff_close'] as $code) {
+    $notificationEmail->templates[$code] = (new \Box\Mod\Email\Entity\EmailTemplate($code))
+        ->setSubject('[Company] [Ticket #{{ ticket.id }}] {{ ticket.subject }}');
+}
+$notificationDi['mod_service'] = $notificationDi->protect(fn ($module) => $notificationEmail);
+$notificationStore = new class {
+    public int $saves = 0;
+    public function save($data): bool { ++$this->saves; return true; }
+};
+$notificationDi['mailgateway_settings'] = $notificationStore;
+$notificationService = new \Box\Mod\Mailgateway\Service();
+$notificationService->setDi($notificationDi);
+if (!$notificationService->getNotificationStatus()['ready']) {
+    throw new RuntimeException('Valid ticket notification templates were rejected');
+}
+$notificationService->saveSettings(['enabled' => '1']);
+$notificationEmail->templates['mod_support_ticket_open']->setEnabled(false);
+$notificationService->saveSettings(['enabled' => '1']);
+if (!$notificationEmail->templates['mod_support_ticket_open']->isEnabled() || $notificationStore->saves !== 2) {
+    throw new RuntimeException('Acknowledgement was not enabled automatically');
+}
+$notificationService->saveSettings(['enabled' => '0']);
+$notificationEmail->templates['mod_support_ticket_open']->setEnabled(true);
+$notificationEmail->templates['mod_support_ticket_staff_reply']->setSubject('Reply without marker');
+if ($notificationService->getNotificationStatus()['ready']) {
+    throw new RuntimeException('Missing staff reply ticket marker accepted');
+}
+$notificationEmail->templates['mod_support_ticket_staff_reply']->setEnabled(false);
+if (!$notificationService->getNotificationStatus()['ready']) {
+    throw new RuntimeException('Optional disabled staff notification rejected');
+}
+unset($notificationEmail->templates['mod_support_ticket_open']);
+if ($notificationService->getNotificationStatus()['ready']) {
+    throw new RuntimeException('Missing acknowledgement template accepted');
+}
+$notificationEmail->templates['mod_support_ticket_staff_reply']->setEnabled(true)->setContent('Keep this body');
+$notificationService->saveSettings(['enabled' => '1']);
+if (!$notificationService->getNotificationStatus()['ready']
+    || $notificationEmail->templates['mod_support_ticket_staff_reply']->getSubject() !== '[Ticket #{{ ticket.id }}] Reply without marker'
+    || $notificationEmail->templates['mod_support_ticket_staff_reply']->getContent() !== 'Keep this body') {
+    throw new RuntimeException('Automatic notification repair failed to preserve wording');
+}
+$updates = $notificationEmail->updates;
+$notificationService->configureNotifications();
+if ($notificationEmail->updates !== $updates) throw new RuntimeException('Repeated notification repair changed valid templates');
+echo "Passed notification readiness, automatic repair, preserved wording, and repeatability.\n";
+
+$notificationAdmin = new class($store) {
+    public bool $ready = true;
+    public function __construct(public $store) {}
+    public function mailgateway_settings_get($data) {
+        return ['settings' => $this->store->getPublic(), 'mailboxes' => $this->store->getAllPublic(),
+            'helpdesks' => [2 => 'General'], 'dependencies' => ['installed' => true, 'available' => false],
+            'notifications' => ['ready' => $this->ready, 'errors' => $this->ready ? [] : ['Template <needs repair>']]];
+    }
+};
+$notificationHtml = $twig->render('settings', ['request' => ['ajax' => false], 'admin' => $notificationAdmin]);
+if (!preg_match('/id="mg-notification-banner"[^>]*hidden/', $notificationHtml)
+    || !str_contains($notificationHtml, 'mailgateway/notifications_setup')) {
+    throw new RuntimeException('Ready notification banner was not hidden or Advanced setup was missing');
+}
+$notificationAdmin->ready = false;
+$notificationHtml = $twig->render('settings', ['request' => ['ajax' => false], 'admin' => $notificationAdmin]);
+if (preg_match('/id="mg-notification-banner"[^>]*hidden/', $notificationHtml)
+    || !str_contains($notificationHtml, 'Template &lt;needs repair&gt;')) {
+    throw new RuntimeException('Notification warnings were hidden or not escaped');
+}
+echo "Passed notification banner visibility, Advanced setup rendering, and warning escaping.\n";
diff --git a/tests/tracking.php b/tests/tracking.php
new file mode 100644
index 0000000..411ec4c
--- /dev/null
+++ b/tests/tracking.php
@@ -0,0 +1,194 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/replies.php';
+require dirname(__DIR__) . '/MessageTracker.php';
+
+$connection = \Doctrine\DBAL\DriverManager::getConnection(['driver' => 'pdo_sqlite', 'memory' => true]);
+$connection->executeStatement('CREATE TABLE mailgateway_message (message_key TEXT PRIMARY KEY, mailbox TEXT, message_id TEXT, payload_hash TEXT, ticket_id INTEGER, result_json TEXT)');
+$connection->executeStatement('CREATE TABLE test_messages (id INTEGER PRIMARY KEY AUTOINCREMENT, ticket_id INTEGER)');
+$trackingService = new class($connection) extends \Box\Mod\Mailgateway\Service {
+    public bool $fail = false;
+    public bool $mismatch = false;
+    public int $notifications = 0;
+    public function __construct(private \Doctrine\DBAL\Connection $connection) {}
+    public function import(array $data): array
+    {
+        $this->connection->insert('test_messages', ['ticket_id' => 41]);
+        if ($this->fail) {
+            throw new RuntimeException('Failure after ticket write');
+        }
+        return ['ticket_id' => 41, 'client_id' => 7];
+    }
+    public function reply(array $data): array
+    {
+        if ($data['ticket_id'] === 999) {
+            throw new \FOSSBilling\InformationException('Ticket not found');
+        }
+        if ($this->mismatch) {
+            throw new \FOSSBilling\InformationException('Sender does not own this ticket');
+        }
+        $this->connection->insert('test_messages', ['ticket_id' => $data['ticket_id']]);
+        return ['ticket_id' => $data['ticket_id'], 'message_id' => 12];
+    }
+    public function notifySenderMismatch(string $sender, int $ticketId): void { ++$this->notifications; }
+};
+$trackingDi = new \Pimple\Container();
+$trackingDi['em'] = new class {
+    public int $clears = 0;
+    public function clear(): void { ++$this->clears; }
+};
+$trackingDi['mod_service'] = $trackingDi->protect(fn ($module) => new class {
+    public function getTicketById($id): void {}
+});
+$trackingService->setDi($trackingDi);
+$tracker = new \Box\Mod\Mailgateway\MessageTracker($connection);
+$data = ['mailbox' => 'support@dev.sebs.space', 'message_id' => '<initial@example.com>',
+    'sender_email' => 'customer@example.com', 'subject' => 'Test', 'content' => 'Test content'];
+$initial = $tracker->process($data, $trackingService);
+$duplicate = $tracker->process($data, $trackingService);
+if ($initial['action'] !== 'ticket' || $initial['duplicate'] || !$duplicate['duplicate']
+    || (int) $connection->fetchOne('SELECT COUNT(*) FROM test_messages') !== 1) {
+    throw new RuntimeException('Duplicate created another ticket');
+}
+$expectRejected = function (array $input) use ($tracker, $trackingService): void {
+    try {
+        $tracker->process($input, $trackingService);
+        throw new RuntimeException('Invalid tracked message accepted');
+    } catch (\FOSSBilling\InformationException) {}
+};
+$expectRejected(array_replace($data, ['content' => 'Changed contents']));
+foreach (['bad-id', "<id@example.com>\r\nInjected", '<id example.com>'] as $id) {
+    $expectRejected(array_replace($data, ['message_id' => $id]));
+}
+$replyData = array_replace($data, ['message_id' => '<reply@example.com>', 'subject' => 'Re: [Ticket #41] Test']);
+$result = $tracker->process($replyData, $trackingService);
+if ($result['action'] !== 'reply' || $result['ticket_id'] !== 41) {
+    throw new RuntimeException('Subject failed to match ticket');
+}
+foreach ([
+    'Re: [Ticket #41] Updated subject',
+    'Fwd: [ticket #41] Test',
+    '[Ticket #41] Re: [Ticket #41] Test',
+] as $index => $subject) {
+    $result = $tracker->process(array_replace($data, ['message_id' => '<subject-' . $index . '@example.com>', 'subject' => $subject]), $trackingService);
+    if ($result['action'] !== 'reply' || $result['ticket_id'] !== 41) {
+        throw new RuntimeException('Valid subject format failed');
+    }
+}
+foreach (['[Ticket #0]', '[Ticket #999999999999999999999999]', '[Ticket #41] [Ticket #42]', '[Ticket #bad]', '[Ticket #41', '[Ticket #999]', "Bad\r\nSubject"] as $index => $subject) {
+    $expectRejected(array_replace($data, ['message_id' => '<invalid-subject-' . $index . '@example.com>', 'subject' => $subject]));
+}
+$unthreaded = $tracker->process(array_replace($data, [
+    'message_id' => '<reference-removed@example.com>', 'subject' => 'A new request',
+    'in_reply_to' => '<initial@example.com>', 'references' => '<unknown@example.com>',
+]), $trackingService);
+if ($unthreaded['action'] !== 'ticket') {
+    throw new RuntimeException('Removed subject reference did not create a new request');
+}
+$duplicateReply = $tracker->process($replyData, $trackingService);
+if (!$duplicateReply['duplicate'] || $duplicateReply['action'] !== 'reply') {
+    throw new RuntimeException('Repeated reply was not deduplicated');
+}
+$isolation = $tracker->process(array_replace($data, ['mailbox' => 'different@example.com']), $trackingService);
+if ($isolation['duplicate']) {
+    throw new RuntimeException('Separate mailboxes incorrectly share deduplication state');
+}
+
+$count = (int) $connection->fetchOne('SELECT COUNT(*) FROM test_messages');
+$trackingService->fail = true;
+$failed = array_replace($data, ['message_id' => '<retry@example.com>']);
+try {
+    $tracker->process($failed, $trackingService);
+    throw new LogicException('Simulated failure was swallowed');
+} catch (RuntimeException $error) {
+    if ($error->getMessage() !== 'Failure after ticket write') {
+        throw $error;
+    }
+}
+if ((int) $connection->fetchOne('SELECT COUNT(*) FROM test_messages') !== $count) {
+    throw new RuntimeException('Partial write survived rollback');
+}
+$trackingService->fail = false;
+$tracker->process($failed, $trackingService);
+$tracker->process($failed, $trackingService);
+if ((int) $connection->fetchOne('SELECT COUNT(*) FROM test_messages') !== $count + 1) {
+    throw new RuntimeException('Retry created duplicate writes');
+}
+$trackingService->mismatch = true;
+$expectRejected(array_replace($replyData, ['message_id' => '<mismatch@example.com>']));
+if ($trackingService->notifications !== 1 || $connection->isTransactionActive()) {
+    throw new RuntimeException('Mismatch notification or transaction cleanup failed');
+}
+echo "Passed persistent deduplication, conflicting payload rejection, subject matching, mailbox isolation, malformed/conflicting/missing ticket rejection, removed references, rollback/retry, and mismatch notifications.\n";
+
+// Exercise the real rejection path with a queue spy that cannot be rolled back.
+$rejectionConnection = \Doctrine\DBAL\DriverManager::getConnection(['driver' => 'pdo_sqlite', 'memory' => true]);
+$rejectionConnection->executeStatement('CREATE TABLE mailgateway_message (message_key TEXT PRIMARY KEY, mailbox TEXT, message_id TEXT, payload_hash TEXT, ticket_id INTEGER, result_json TEXT)');
+$rejectionConnection->executeStatement('CREATE TABLE mailgateway_notification (sender_key TEXT PRIMARY KEY, last_notified_at INTEGER NOT NULL)');
+$rejectionConnection->executeStatement('CREATE TABLE client (id INTEGER PRIMARY KEY, email TEXT)');
+$rejectionDi = new \Pimple\Container();
+$rejectionDi['dbal'] = $rejectionConnection;
+$rejectionEm = new class {
+    public int $clears = 0;
+    public function clear(): void { ++$this->clears; }
+};
+$rejectionDi['em'] = $rejectionEm;
+$rejectionDi['logger'] = new class {
+    public function warning(...$args): void {}
+};
+$rejectionEmail = new class {
+    public array $attempts = [];
+    public bool $fail = false;
+    public function sendTemplate($data): bool {
+        $this->attempts[] = $data;
+        if ($this->fail) throw new RuntimeException('Queue unavailable');
+        return true;
+    }
+};
+$rejectionDi['mod_service'] = $rejectionDi->protect(fn ($module) => $module === 'email' ? $rejectionEmail : $support);
+$rejectionLimiter = new class($rejectionConnection, $rejectionEm) {
+    public array $entries = [];
+    public function __construct(private $connection, private $em) {}
+    public function run($sender, $queue): bool {
+        $this->entries[] = ['active' => $this->connection->isTransactionActive(),
+            'tracked' => (int) $this->connection->fetchOne('SELECT COUNT(*) FROM mailgateway_message'),
+            'clears' => $this->em->clears];
+        return (new \Box\Mod\Mailgateway\NotificationCooldown($this->connection))->run($sender, $queue);
+    }
+};
+$rejectionDi['mailgateway_notification_cooldown'] = $rejectionLimiter;
+$rejectionService = new \Box\Mod\Mailgateway\Service();
+$rejectionService->setDi($rejectionDi);
+$rejectionTracker = new \Box\Mod\Mailgateway\MessageTracker($rejectionConnection);
+foreach (['guest', 'customer', 'ambiguous', 'queue-failure'] as $index => $case) {
+    $ticket->setClientId($case === 'guest' || $case === 'queue-failure' ? null : 7);
+    $ticket->setAuthorEmail('owner@example.com');
+    $rejectionConnection->executeStatement('DELETE FROM client');
+    $rejectionConnection->executeStatement('DELETE FROM mailgateway_notification');
+    $rejectionConnection->insert('client', ['id' => 8, 'email' => 'other@example.com']);
+    if ($case === 'ambiguous') {
+        $rejectionConnection->insert('client', ['id' => 7, 'email' => 'other@example.com']);
+    }
+    $rejectionEmail->fail = $case === 'queue-failure';
+    $input = ['mailbox' => 'support@example.com', 'message_id' => "<rejection-$index@example.com>",
+        'sender_email' => 'other@example.com', 'subject' => '[Ticket #4] Reply', 'content' => 'Rejected reply'];
+    try {
+        $rejectionTracker->process($input, $rejectionService);
+        throw new RuntimeException('Real mismatched reply accepted');
+    } catch (\FOSSBilling\InformationException $error) {
+        $expected = $ticket->isGuestTicket() ? 'Sender does not own this ticket' : 'Sender does not uniquely match the ticket owner';
+        if ($error->getMessage() !== $expected) throw $error;
+    }
+    if (count($rejectionEmail->attempts) !== $index + 1
+        || count($rejectionLimiter->entries) !== $index + 1
+        || $rejectionLimiter->entries[$index] !== ['active' => false, 'tracked' => 0, 'clears' => $index + 1]
+        || $rejectionConnection->isTransactionActive()
+        || (int) $rejectionConnection->fetchOne('SELECT COUNT(*) FROM mailgateway_notification') !== ($rejectionEmail->fail ? 0 : 1)
+        || $rejectionEmail->attempts[$index] !== ['to' => 'other@example.com',
+            'code' => 'mailgateway_sender_mismatch', 'sender_email' => 'other@example.com', 'ticket_id' => 4]) {
+        throw new RuntimeException('Rejected reply did not attempt exactly one safe notification after rollback');
+    }
+}
+echo "Passed real guest/customer/ambiguous rejection paths, single post-rollback notification attempts, and queue-failure cleanup.\n";
diff --git a/tests/validation.php b/tests/validation.php
new file mode 100644
index 0000000..ac83cc5
--- /dev/null
+++ b/tests/validation.php
@@ -0,0 +1,192 @@
+<?php
+
+declare(strict_types=1);
+
+require dirname(__DIR__, 3) . '/vendor/autoload.php';
+define('PATH_CONFIG', __DIR__ . '/config.php');
+define('DEBUG', false);
+require dirname(__DIR__) . '/RuntimeConfig.php';
+require dirname(__DIR__) . '/DependencyInstaller.php';
+require dirname(__DIR__) . '/Service.php';
+require dirname(__DIR__) . '/InboundPolicy.php';
+require dirname(__DIR__) . '/NotificationCooldown.php';
+require dirname(__DIR__) . '/NotificationEmailProxy.php';
+require dirname(__DIR__) . '/Settings.php';
+require dirname(__DIR__) . '/Api/Admin.php';
+
+$service = new \Box\Mod\Mailgateway\Service();
+$valid = ['sender_email' => 'customer@example.com', 'subject' => 'Test', 'content' => 'Test body'];
+$cases = [
+    [],
+    array_replace($valid, ['sender_email' => ['customer@example.com']]),
+    array_replace($valid, ['sender_email' => 'Name <customer@example.com>']),
+    array_replace($valid, ['subject' => "Header\r\nInjected"]),
+    array_replace($valid, ['subject' => str_repeat('x', 256)]),
+    array_replace($valid, ['subject' => "\xFF"]),
+    array_replace($valid, ['content' => str_repeat('x', 65536)]),
+    array_replace($valid, ['content' => "\xFF"]),
+    array_replace($valid, ['content' => "\0"]),
+    array_replace($valid, ['sender_name' => ['Invalid']]),
+    array_replace($valid, ['sender_name' => "Name\nInjected"]),
+    array_replace($valid, ['sender_name' => str_repeat('x', 256)]),
+];
+foreach ($cases as $index => $data) {
+    try {
+        $service->import($data);
+        throw new \RuntimeException('Invalid input accepted: ' . $index);
+    } catch (\FOSSBilling\InformationException) {
+        // Must reject before accessing any database services.
+    }
+}
+
+// The production API exposes only the settings page operations.
+$methods = array_filter((new ReflectionClass(\Box\Mod\Mailgateway\Api\Admin::class))->getMethods(ReflectionMethod::IS_PUBLIC),
+    fn ($method) => $method->getDeclaringClass()->getName() === \Box\Mod\Mailgateway\Api\Admin::class);
+$names = array_map(fn ($method) => $method->getName(), $methods);
+sort($names);
+if ($names !== ['install_dependencies', 'mailbox_delete', 'notifications_setup', 'settings_get', 'settings_save', 'setup', 'test_connection']) {
+    throw new RuntimeException('Unexpected production API endpoints');
+}
+echo 'Passed ', count($cases), " invalid-input checks and production API surface check.\n";
+
+// Exercise the import orchestration with real ticket entities and a simulated
+// Support autoresponse, without requiring a database or sending email.
+$client = new class extends \Model_Client {
+    public function __get($property)
+    {
+        return $property === 'id' ? 7 : null;
+    }
+};
+foreach (['on_hold' => 1, 'open' => 0, 'closed' => 0] as $status => $expectedFlushes) {
+    $ticket = new \Box\Mod\Support\Entity\SupportTicket();
+    $ticket->setStatus($status);
+    $helpdesk = new \Box\Mod\Support\Entity\Helpdesk();
+    $support = new class($ticket, $helpdesk, $client) {
+        public function __construct(public $ticket, public $helpdesk, public $client) {}
+        public function getHelpdeskRepository() { return $this; }
+        public function findBy($criteria, $order, $limit) { return [$this->helpdesk]; }
+        public function ticketCreateForClient($client, $helpdesk, $data): int
+        {
+            if ($client !== $this->client || $helpdesk !== $this->helpdesk || $data['content'] !== 'Test body') {
+                throw new \RuntimeException('Incorrect customer or message passed to Support');
+            }
+            return 42;
+        }
+        public function getTicketById(int $id) { return $this->ticket; }
+        public function toApiArray($ticket, $deep, $identity)
+        {
+            if ($identity !== $this->client) {
+                throw new \RuntimeException('Notification uses incorrect customer');
+            }
+            return ['id' => 42];
+        }
+    };
+    $em = new class {
+        public int $flushes = 0;
+        public function flush(): void { ++$this->flushes; }
+    };
+    $di = new \Pimple\Container();
+    $di['dbal'] = new class {
+        public function fetchFirstColumn($sql, $params) { return [7]; }
+    };
+    $di['db'] = new class($client) {
+        public function __construct(public $client) {}
+        public function getExistingModelById($type, $id) { return $this->client; }
+    };
+    $di['em'] = $em;
+    $di['mailgateway_settings'] = new class {
+        public function get(): array { return ['support_helpdesk_id' => null]; }
+    };
+    $di['mailgateway_notification_cooldown'] = new class {
+        public function run($sender, $queue): bool { return $queue() !== false; }
+    };
+    $di['auth'] = new class {
+        public function isClientLoggedIn(): bool { return false; }
+    };
+    $email = new class {
+        public array $messages = [];
+        public function sendTemplate($data) { $this->messages[] = $data; }
+    };
+    $di['mod_service'] = $di->protect(fn ($module) => $module === 'email' ? $email : $support);
+    $service->setDi($di);
+    $result = $service->import($valid);
+    $expectedStatus = $status === 'on_hold' ? 'open' : $status;
+    if ($ticket->getStatus() !== $expectedStatus || $em->flushes !== $expectedFlushes
+        || $result['ticket_id'] !== 42 || $result['client_id'] !== 7) {
+        throw new \RuntimeException('Import status regression: ' . $status);
+    }
+    if ($email->messages !== [['to_client' => 7, 'code' => 'mod_support_ticket_open', 'ticket' => ['id' => 42]]]) {
+        throw new \RuntimeException('Customer acknowledgement missing or incorrect');
+    }
+}
+echo "Passed autoresponse status check, existing Open/Closed status checks, and customer identity forwarding.\n";
+echo "Passed customer acknowledgement recipient, template, and ticket-number checks.\n";
+
+$guestSupport = new class {
+    public array $received = [];
+    public bool $enabled = true;
+    public function getHelpdeskRepository() { return $this; }
+    public function findBy($criteria, $order, $limit)
+    {
+        $helpdesk = new \Box\Mod\Support\Entity\Helpdesk();
+        (new \ReflectionProperty($helpdesk, 'id'))->setValue($helpdesk, 3);
+        return [$helpdesk];
+    }
+    public function ticketCreateForGuest($data): string
+    {
+        if (!$this->enabled) {
+            throw new \FOSSBilling\InformationException('Guest tickets disabled');
+        }
+        $this->received[] = $data;
+        return 'private-access-hash';
+    }
+    public function findOneByHash($hash)
+    {
+        if ($hash !== 'private-access-hash') {
+            throw new \RuntimeException('Guest hash lookup incorrect');
+        }
+        $ticket = new \Box\Mod\Support\Entity\SupportTicket();
+        (new \ReflectionProperty($ticket, 'id'))->setValue($ticket, 43);
+        return $ticket;
+    }
+};
+$guestDi = new \Pimple\Container();
+$lookup = new class {
+    public array $ids = [];
+    public function fetchFirstColumn($sql, $params) { return $this->ids; }
+};
+$guestDi['dbal'] = $lookup;
+$guestDi['mailgateway_settings'] = new class {
+    public function get(): array { return ['support_helpdesk_id' => null]; }
+};
+$guestDi['mod_service'] = $guestDi->protect(fn ($module) => $guestSupport);
+$service->setDi($guestDi);
+foreach ([null, 'Guest Sender'] as $name) {
+    $data = $valid;
+    if ($name !== null) {
+        $data['sender_name'] = $name;
+    }
+    $result = $service->import($data);
+    $received = $guestSupport->received[array_key_last($guestSupport->received)];
+    if ($result !== ['ticket_id' => 43, 'client_id' => null, 'support_helpdesk_id' => 3]
+        || $received !== ['name' => $name ?? $valid['sender_email'], 'email' => $valid['sender_email'],
+            'subject' => 'Test', 'content' => 'Test body', 'support_helpdesk_id' => 3]) {
+        throw new \RuntimeException('Guest import or attribution incorrect');
+    }
+}
+$guestSupport->enabled = false;
+try {
+    $service->import($valid);
+    throw new \RuntimeException('Disabled guest policy bypassed');
+} catch (\FOSSBilling\InformationException) {
+}
+$lookup->ids = [7, 8];
+try {
+    $service->import($valid);
+    throw new \RuntimeException('Ambiguous customer accepted');
+} catch (\FOSSBilling\InformationException) {
+}
+if (count($guestSupport->received) !== 2) {
+    throw new \RuntimeException('Unexpected guest creation');
+}
+echo "Passed guest routing, sender name fallback, helpdesk mapping, private hash handling, disabled guest policy, and ambiguous customer rejection.\n";
diff --git a/tools/poll.php b/tools/poll.php
new file mode 100644
index 0000000..994bf07
--- /dev/null
+++ b/tools/poll.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+if (PHP_SAPI !== 'cli') {
+    http_response_code(404);
+    exit;
+}
+if (count($argv) > 2 || (isset($argv[1]) && $argv[1] !== '--force')) {
+    fwrite(STDERR, "Usage: php tools/poll.php [--force]\n");
+    exit(1);
+}
+require dirname(__DIR__, 3) . '/load.php';
+try {
+    $result = $di['mod_service']('mailgateway')->poll(($argv[1] ?? '') === '--force');
+    echo json_encode($result, JSON_PRETTY_PRINT | JSON_THROW_ON_ERROR), PHP_EOL;
+    $failed = array_filter($result['mailboxes'], fn ($mailbox) => $mailbox['status'] !== 'completed'
+        || $mailbox['failed'] > 0 || $mailbox['retry_pending'] > 0 || $mailbox['move_pending'] > 0);
+    exit($failed === [] ? 0 : 2);
+} catch (Throwable) {
+    fwrite(STDERR, "Mail Gateway polling failed. Check the module tables, configuration, and cron logs.\n");
+    exit(1);
+}
diff --git a/tools/setup.php b/tools/setup.php
new file mode 100644
index 0000000..0604f9d
--- /dev/null
+++ b/tools/setup.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+if (PHP_SAPI !== 'cli') {
+    http_response_code(404);
+    exit;
+}
+
+require dirname(__DIR__, 3) . '/load.php';
+$di['mod_service']('mailgateway')->setup();
+echo "Mail Gateway tables and sender-mismatch email template are ready.\n";
diff --git a/tools/test-imap.php b/tools/test-imap.php
new file mode 100644
index 0000000..7233926
--- /dev/null
+++ b/tools/test-imap.php
@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+if (PHP_SAPI !== 'cli') {
+    http_response_code(404);
+    exit;
+}
+
+$createFolders = false;
+$mailboxId = null;
+foreach (array_slice($argv, 1) as $argument) {
+    if ($argument === '--create-folders') {
+        $createFolders = true;
+    } elseif (str_starts_with($argument, '--mailbox=')) {
+        $mailboxId = substr($argument, strlen('--mailbox='));
+    } else {
+        fwrite(STDERR, "Usage: php tools/test-imap.php [--mailbox=email-or-id] [--create-folders]\n");
+        exit(1);
+    }
+}
+
+require dirname(__DIR__, 3) . '/load.php';
+try {
+    $store = new \Box\Mod\Mailgateway\Settings($di);
+    $mailboxes = $store->getAll();
+    $id = $mailboxId;
+    if ($id === null) {
+        $id = isset($mailboxes['default']) ? 'default' : array_key_first($mailboxes);
+    } elseif (str_contains($id, '@')) {
+        $id = null;
+        foreach ($mailboxes as $candidate => $mailbox) {
+            if (strcasecmp($mailbox['mailbox'], $mailboxId) === 0) {
+                $id = $candidate;
+                break;
+            }
+        }
+    }
+    if ($id === null) {
+        throw new \FOSSBilling\InformationException('Mailbox not found');
+    }
+    $settings = $store->get($id);
+    printf("Checking %s at %s:%d using %s with certificate validation enabled...\n",
+        $settings['mailbox'], $settings['host'], $settings['port'],
+        $settings['encryption'] === 'ssl' ? 'implicit TLS' : 'STARTTLS');
+    $result = (new \Box\Mod\Mailgateway\ImapConnectionTest())->test($settings, $createFolders);
+    // A read-only check does not change the saved readiness state.
+    if ($createFolders) {
+        $store->recordTest($id, $settings, $result);
+    }
+    echo $result['connected'] ? "IMAP login succeeded.\n" : "IMAP login failed.\n";
+    if ($result['connected']) {
+        echo 'Native MOVE support: ', $result['move_supported'] === true ? 'available' : 'unavailable or unverified', PHP_EOL;
+    }
+    foreach ($result['folders'] as $folder) {
+        printf("%s — %s\n", $folder['path'], $folder['error']
+            ?? ($folder['created'] ? 'created' : ($folder['exists'] ? 'found' : 'MISSING')));
+    }
+    foreach ($result['errors'] as $error) {
+        fwrite(STDERR, $error . PHP_EOL);
+    }
+    echo $createFolders ? "Folder setup finished. " : "Read-only check finished. ";
+    echo "No messages were fetched, marked, moved, deleted, or imported.\n";
+    exit($result['success'] ? 0 : ($result['connected'] && $result['move_supported'] === true ? 2 : 1));
+} catch (\FOSSBilling\InformationException $error) {
+    fwrite(STDERR, $error->getMessage() . PHP_EOL);
+    exit(1);
+} catch (\Throwable $error) {
+    fwrite(STDERR, 'IMAP check could not complete (' . $error::class . "). Check the module configuration and tables.\n");
+    exit(1);
+}