Fatal error: Uncaught Error: Class "ilXmlWriter" not found in /var/www/html/ilias/components/ILIAS/Course/classes/class.ilCourseXMLWriter.php:31 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/Course/classes/class.ilCourseXMLWriter.php on line 31