Fatal error: Uncaught Error: Interface "ilCalendarScheduleFilter" not found in /var/www/html/ilias/components/ILIAS/Course/classes/Timings/class.ilCalendarScheduleFilterTimings.php:25 Stack trace: #0 {main} thrown in /var/www/html/ilias/components/ILIAS/Course/classes/Timings/class.ilCalendarScheduleFilterTimings.php on line 25