898
this actually happened rule
(kbin.run)
Be sure to follow the rule before you head out.
Rule: You must post before you leave.
You can only do this if you have the signing keys. If the store wants to do this for users (say, if the developer is incapacitated somehow) they can't.
Edit: I'm actually not 100% sure if the signing keys are required for changing just the version number, but I assume so
That sounds about right for Google play. That said, the point still stands. If Google wanted to implement such a feature, it could probably be done by onky patching things on their store backend. I'm sure it wouldn't be a trivial change, but still it wouldn't need to touch the OS itself. Probably. As far as the phone is concerned, it would still be disallowing rollbacks as usual.