this was announced a year ago https://www.macrumors.com/2022/12/07/new-imessage-apple-id-s...

Its unlikely. They had pre-existing infrastructure for this via their Apple Messages For Business[0] program, which includes all the backbone to show that the account is verified (including the checkmark and info tab). This appears to be an extension of that for consumer accounts

[0]: https://register.apple.com/resources/messages/messaging-docu...

No, this feature has been in beta builds for quite a while.

> gaining access to the iMessage network?

I wouldn't say they "gained access to iMessage network".

They figured out a weakness in Apple's authentication that allowed a user with a fake serial # to authenticate. Apple is slowly making it more strict/checking the serial #s better (my opinion/guess).

I think it would be hard to push out such a feature in such a short span. Beeper’s userbase is tiny and not an immediate security threat to Apple.

Unlikely.