We are attempting to upgrade a Moodle site from 3.8.5 to 3.9.4 and have hit some issues with the process. The most obvious problem is that all of the course configurations seem to be corrupted.
Courses were topics format, with ~ 5 or 6 topics/sections each with a couple of activities, in the 3.8.5 version. Sections had availability conditions, e.g. reveal when a quiz in the previous section is complete or a scorm pack etc.
After the upgrade to 3.9.4, now all courses are set as "single activity" format with an activity type of "forum". Because this activity doesn't exist, you are taken to the "Add a forum activity" page (as an admin). If I go into the course settings and restore it to "topics" format, then the activities all reappear, along with the topics themselves, but the activities are now all in the first topic, the topic availability conditions have gone and all of the topics are hidden from students. We do not seem to have lost activity/course completion data.
I *could* recreate all of the course setups, but this is not without significant effort.
I am aware of this in the release notes: https://docs.moodle.org/dev/Moodle_3.9.4_release_notes#Warning_-_courses_with_many_sections however this is not a custom course format and it's not more than 52 sections. Topics does not define the max sections, the default in /course/format/lib.php should apply, which is 52. moodlecourse:maxsections is also 52 in the prefix_config_plugins database table. This should not be the cause.
We are re-running the update using 3.9.3 instead and will update this thread if the same issue happens there, but has anyone else experienced this and does anyone have any ideas what we might do to enable us to use the current LTS version?