Uhhhh, what does APNS have to do with any of this?
Correct me if I'm wrong, but people want iMessage to be an open protocol. You're talking about APNS, the "apple push notification service", which is something completely different than what beeper is doing and what folks are asking for. The message schema, format, types, encoding, max length, delivery guarantees, etc, like jabber/xmpp [1]. Push notifications are sent for iMessage, but that isn't what people want to be turned into an open protocol