Bug fixes and other improvements We've created an updated version of Beeper Mini that fixes an issue that caused messages not to be sent or received. You can get the update directly from beeper.com/update on your phone. We are still doing some final testing before submitting the update to the Google Play Store for distribution to all users. If you encounter any issues, you may need to uninstall and reinstall the app.
They intend to work with lots of services, it’s just that imessage is getting the most focus right now.
If im not mistaken, they intend to eventually open source the code, so facebook/apple/google better buy quick.