iMessage on old iPhone So in the past few days I just retired my old iPhone 5 and upgraded to the new iPhone 6.

Once I took the SIM out, I expected just standard carrier calls and texts to stop working (for obvious reasons) but for some reason all forms of iMessage seem to have stopped working too.

For many reasons I intend on still using the iPhone 5 without a SIM so is they're any reason as to why iMessage stopped working? I thought it would have assumed the functionality of what would essentially be a very large iPod touch.

Enabling and disabling it in settings hasn't done much, yet it is activated successfully upon turning it on. I don't receive messages anymore and sending messages causes it to instantly fail.
This seems to be related to Apple's attempt to make it so that if you are moving from iOS to Android other iOS users can still message you as your iMessage will be disabled.

I managed to get a friend's phone to work by sending him an iMessage to his Apple ID. This seemed to fix it and now he can send/receive messages with others too.