September 30 started a phone-side check on who made the app. I wrote what a Flutter app on Play needs. The action was smaller than the headline: open Console and look.
99% is not a yes
Google says most Play apps were registered. If anything shows as not registered, register it there. That is the check.
Signing keys
Play App Signing means the fingerprint you think you have may not be the one the phone sees. The original post is where I put that. This post is the habit: look, do not assume.
2027
The first wave is four countries. Wider later. I would rather find a gap in Console than in a blocked install.