It probably isn't feasible to recreate the actual memory error while testing, so here are testing instructions to confirm the upgrade step still works after the change: Install Moodle 3.10.x. Create a course. Add an activity module. Using the 'Restrict access' section of the settings form, add a 'User profile field' condition on the 'ICQ' field being 'frog', Upgrade your site to Moodle 3.11+ (including this change). Look at the activity module and verify that it still has a user profile field condition on the ICQ field being 'frog'. For a 'real' test, I tested on our system that had this problem before the change (~650k course_modules entries of which ~50k actually have an availability set) and it ran through the upgrade step quickly (1.5 seconds).