I seem to have a problem with my main course after I upgraded from 3.8.
All the other courses are fine but one gives the following error:
Coding error detected, it must be fixed by a programmer: Function get_categories() is removed. Please use appropriate functions from class core_course_category.
I have looked everywhere but cannot find anything. It still works on my other site with 3.8 and I have compared all plugins etc. but I am at a loss.
Any help will be appreciated.