Just upgraded to Klass v3.6.1 2018121000. Only one of the 2 bugs I reported to their Github has been solved. In debug mode I still see 3 error messages on the front page:
Class coursecat is now alias to autoloaded class core_course_category, course_in_list is an alias to core_course_list_element. Class coursecat_sortable_records is deprecated without replacement. Do not include coursecatlib.php etc.
@Filippo, I do not see this problem, my courses are listed OK.