I've read that there's a way to lock an app (prevent it from updating) via ADB but not having much luck on finding how to do it on Android TV and the only instructions I'm finding for it on Android is via the Play Store UI, but that option isn't available on Android TV.
Anyone have any idea how to keep a single app from updating?
You can sideload the old APK. If it's a free app, you can also delete it from your library of purchased apps. You can do that on your phone's Play store interface. Play store will then think you don't own that app anymore. If that still doesn't work, try to re-sign the APK with your own key ( https://stackoverflow.com/questions/10930331/how-to-sign-an-already-compiled-apk ). That way the new version on Play store won't be able to update over it because of different signatures.
I have an old version of Viki (Android TV version) sideloaded on my box. It was re-signed and never gets updated. It doesn't even show up on the list of installed apps in Play store probably because I never installed it from there in the first place (so I never really own it in my account).