Fatal error: Uncaught Error: Class "Sabre\DAV\Collection" not found in /home/tzuovhm/tzuovhm/apps_/dav/lib/CalDAV/PublicCalendarRoot.php:15 Stack trace: #0 {main} thrown in /home/tzuovhm/tzuovhm/apps_/dav/lib/CalDAV/PublicCalendarRoot.php on line 15