Fatal error: Uncaught Error: Class "OCP\AppFramework\Middleware" not found in /var/www/html/nextcloud/apps/app_api/lib/Middleware/ExAppUiMiddleware.php:21 Stack trace: #0 {main} thrown in /var/www/html/nextcloud/apps/app_api/lib/Middleware/ExAppUiMiddleware.php on line 21