There's people working on decompiling the APK and reinstalling the missing APIs etc.
The one I posted doesn't work on firesticks but works a charm on other android. Some features like the new HD section are working properly but it looks like a group of Devs on Reddit are taking on the project
I don't know enough about it to comment, this approach seems to have worked though:
You can add your own api keys:
Trakt api key, fanart tv api key, tmdb api key and then everything works as it should. You can register on those sites to get the api keys for free, then decompile the apk, mod the relevant files with your own api keys, repack/sign and then the apk works fine again.
Tested and working - someone nice might release a modded public version - probably in a day or two (won't be me though).