public static function enableMaintenanceMode()
    {
        $config = Config::getInstance();

        $tracker = $config->Tracker;
        $tracker['record_statistics'] = 0;
        $config->Tracker = $tracker;

        $general = $config->General;
        $general['maintenance_mode'] = 1;
        $config->General = $general;

        $config->forceSave();
    }