Fatal error: Uncaught Error: Interface "OCP\Activity\IProvider" not found in /home/tzuovhm/tzuovhm/apps_/dav/lib/CardDAV/Activity/Provider/Base.php:20 Stack trace: #0 {main} thrown in /home/tzuovhm/tzuovhm/apps_/dav/lib/CardDAV/Activity/Provider/Base.php on line 20