[ds]

Technically speaking, Beeper can keep working for a long time. That is, Until apple starts checking if the client is on a official apple device. This may or may not be feasible for Apple to implement, mostly depending on if they even have the resources/method to know if every device is legitimate or not (they may not- especially for older devices)

If they do have a way to enforce 'authentic' devices, the only step after that for beeper to take will be to ask users to purchase the cheapest iphone that still works for imessage and to extract its serial/key/whatever to import into the android client.