Yep, this could have been the problem for you, Joel, but not for me. When I upgrade my Moodle, I always install the latest versions of plugins, so I already have that version of Collapsed Topics installed. This is probably why I did not encounter any problems.
Upgrading Moodle and plugins at the same time is something that I have built into my workflow.
Upgrading Moodle and plugins at the same time is something that I have built into my workflow.