Fatal error: Uncaught Error: Interface 'OCA\Activity\Formatter\IFormatter' not found in /home/mattiapa/cloud2.mprnl.fr/owncloud/apps/activity/lib/Formatter/GroupFormatter.php:28 Stack trace: #0 {main} thrown in /home/mattiapa/cloud2.mprnl.fr/owncloud/apps/activity/lib/Formatter/GroupFormatter.php on line 28