Did I miss something? I don't find that in the nb184 release notes and remember this post (→ first sentence): https://community.appinventor.mit.edu/t/androidx-libraries/4278/3?u=anke
"Certainly not in the near future and possibly not for quite a while."
However, this is good news because Kodular has to do the same (so that Kodular can update ExoPlayer to the latest version that requires AndroidX).
But why were the extension developers not informed earlier so that they could adapt their extensions on time.