Apple appears to have closed the loophole used by BeeperMini to bring iMessage to Android, so that the blue bubbles no longer appear on Android devices. BeeperMini stopped working earlier today, with users receiving a "Lookup failed on server: Lookup request timed out" error message.
Beeper said on Twitter it was investigating the issue, but Beeper CEO Eric Migicovsky said "all the data" suggests Apple has actually found a way to prevent the Beeper Mini from working.
Launched on Tuesday, BeeperMini uses reverse-engineered iMessage protocols and encryption technology, leveraging Apple's own iMessage servers, to allow Android users to send blue bubble iMessages to iPhone users. The app supports all iMessage features, including read receipts, typing tips, reactions, and more.
BeeperMini does not require an AppleID login, unlike other less secure Android iMessage apps like Sunbird. How BeeperMini works is explained in depth in a blog post, giving Apple some insight into how it works. BeeperMini uses reverse engineering by security researcher jjtech, who also outlined his approach and shared a proof-of-concept implementation of iMessage on Github.
The app communicates directly with Apple's iMessage servers and registers the Beeper user's phone number as an iMessage user to allow Blue Bubble access. Following BeeperMini's release, there was immediate speculation that Apple would shut it down, but given the way it mimics real iMessage users, it's unclear whether Apple could do that.
Apple seems to have found a way, so this may be the end of the BeeperMini. Migicovsky said the company will "evaluate options" to figure out what this means for the future of the app.