Fatal error: Uncaught Error: Interface 'Sabre\DAV\ICollection' not found in /home/malert/WebDAV/vendor/sabre/dav/lib/DAV/Sync/ISyncCollection.php:18 Stack trace: #0 {main} thrown in /home/malert/WebDAV/vendor/sabre/dav/lib/DAV/Sync/ISyncCollection.php on line 18