Fatal error: Uncaught Error: Class "OCP\Migration\SimpleMigrationStep" not found in /home/tzuovhm/tzuovhm/apps/notifications/lib/Migration/Version2004Date20190107135757.php:17 Stack trace: #0 {main} thrown in /home/tzuovhm/tzuovhm/apps/notifications/lib/Migration/Version2004Date20190107135757.php on line 17