Fatal error: Uncaught Error: Interface "ILIAS\Container\Content\Block" not found in /var/www/html/ilias/components/ILIAS/Container/Content/Block/class.ItemGroupBlock.php:27 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/Container/Content/Block/class.ItemGroupBlock.php on line 27