Upgraded to Catalina, using Karabiner Elements - KM not responding to keys

I was using KM just fine with Mojave combined with Karabiner Elements. I just upgraded to Catalina. Now when I'm running Karabiner Elements and I try to specify a trigger key in KM, I just get "try again". Any ideas? I do pretty much need Karabiner Elements to use certain software which is not responding to certain keys on my keyboard without remapping them with KE. I'm using KM 8.2.4.

Wait... I noticed that I was running version 8 in a trial mode and that I had actually purchased version 7. I installed version 7 instead and tried again to recognize a key from my keyboard. It worked this time! I don't know if it's because I'm on version 7 now or because I just restarted KM.

Okay I'm getting some weird behavior like delayed key response, and at one point my f key stopped working. I have that bound to a macro which is supposed to usually have no effect because it types an f under most circumstances. What's strange is that it randomly stopped working even without me doing anything. Can anyone tell me if KM 7 is compatible with my OS (Catalina) and running Karabiner Elements at the same time?