Fatal error: Uncaught Error: Class "OCP\Migration\SimpleMigrationStep" not found in /home/tzuovhm/tzuovhm/nextcloud/apps/activity/lib/Migration/Version2008Date20181011095117.php:18 Stack trace: #0 {main} thrown in /home/tzuovhm/tzuovhm/nextcloud/apps/activity/lib/Migration/Version2008Date20181011095117.php on line 18