Fatal error: Uncaught Error: Interface "Sabre\DAV\ICollection" not found in /home/tzuovhm/tzuovhm/3rdparty_/sabre/dav/lib/CalDAV/ICalendarObjectContainer.php:20 Stack trace: #0 {main} thrown in /home/tzuovhm/tzuovhm/3rdparty_/sabre/dav/lib/CalDAV/ICalendarObjectContainer.php on line 20