Fatal error: Uncaught Error: Class "Sabre\DAV\File" not found in /users/forscher/www/Baikal/vendor/sabre/dav/lib/CalDAV/Notifications/Node.php:23 Stack trace: #0 {main} thrown in /users/forscher/www/Baikal/vendor/sabre/dav/lib/CalDAV/Notifications/Node.php on line 23