I am not following closely but there is a fun cat and mouse game going on right now between Apple and Beeper. 

According to what I was able to gather: Beeper allowed android users to use iMessage. Apple doesn’t provide official API so the team reverse engineered iMessage to build that feature into their products. Apple then changed the backend of iMessage effectively putting a stop to their “hack”. Their account just posted that iMessage is back so I am wondering how long it will take till Apple blocks them again

Beeper Mini is back in operation after Apple’s attempt to shut it down