Fatal error: Uncaught Error: Interface 'Sabre\DAV\ICollection' not found in /home/mattiapa/cloud2.mprnl.fr/owncloud/apps/customgroups/lib/Dav/GroupMembershipCollection.php:39 Stack trace: #0 {main} thrown in /home/mattiapa/cloud2.mprnl.fr/owncloud/apps/customgroups/lib/Dav/GroupMembershipCollection.php on line 39