>> My guess is that you think iMessage is SMS-only
> No, there's Apple's proprietary protocol...
Earlier you asked: "But iMessage is already open?"
Now you are saying that iMessage uses "Apple's proprietary protocol". I hope now you understand that when people say that Apple iMessage is not open, they are not talking about the SMS protocol that Apple does not own.
> No, there's Apple's proprietary protocol...
Earlier you asked: "But iMessage is already open?"
Now you are saying that iMessage uses "Apple's proprietary protocol". I hope now you understand that when people say that Apple iMessage is not open, they are not talking about the SMS protocol that Apple does not own.