Fatal error: Uncaught Error: Class "OCP\Migration\SimpleMigrationStep" not found in /home/tzuovhm/tzuovhm/apps_/mail/lib/Migration/Version0161Date20190902103559.php:17 Stack trace: #0 {main} thrown in /home/tzuovhm/tzuovhm/apps_/mail/lib/Migration/Version0161Date20190902103559.php on line 17