I'm trying to update a plugin that I've submitted before as an "alpha" release as an updated "stable" release.
When I first uploaded my update, I soon got a message back that I had an incompatibility problem with 2019.3.5 (IU-193.7288.26) of IDEA, an earlier version.
The error didn't make much sense, as I was able to run my code just fine on that release, nevertheless I changed the code to avoid the NotificationGroup constructor the report called out, and submitted another update.
Now I had a huge number of problems with the latest release of IDEA, 2020.2 (IU-202.6397.94) which I didn't have just yesterday. All of a sudden, dozen of basic IntelliJ API classes were listed with "Failed to read class" errors.
What has changed!? It wasn't a change I made that would have done this!