Fatal error: Uncaught Error: Class "ILIAS\UI\Implementation\Component\Tree\Node\Simple" not found in /var/www/html/ilias/components/ILIAS/UI/src/Implementation/Component/Tree/Node/KeyValue.php:27 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/UI/src/Implementation/Component/Tree/Node/KeyValue.php on line 27