We recently upgraded from Moodle 2.7 to Moodle 2.8.1 and since the upgrade we have been unable to edit a quiz. To determine what was happening we turned on Debug and got the following error message.
Fatal error: Call to undefined function mod_quiz\output\question_get_category_id_from_pagevars() in /var/www/html/mod/quiz/classes/output/edit_renderer.php on line 471
Currently we have no idea how to fix this problem. However, without the ability to quiz our students, a function we use extensively on Moodle, the usability of Moodle has decreased substantially. Any ideas how to fix this problem?