Open Radar

 
Summary:
If a person unregisters from iMessage, group conversations are still sent through iMessage and are never received by the person who unregistered.

Steps to Reproduce:
1. Activate three iPhones. (Call them Alan, Betty, and Charlie's phones.)
2. Start a group iMessage from one to the other two.
3. Deactivate iMessage on Alan's iPhone.
4. Move Alan's SIM card to an Android phone.
5. Send a message from Betty's phone to the group thread.

Expected Results:
I expect the message to be delivered to the recipients over SMS (green bubbles) since Alan no longer uses iMessage.

Actual Results:
To Betty, the message appears to be sent successfully.

Charlie receives the message because he has iMessage.

Alan is never notified of the message because he only has SMS and the message was sent over iMessage.

Version:
This issue persists with all devices running the latest version of iOS.

Notes:
Individual (non-group) conversations revert to SMS as expected.

If Betty deletes the entire group thread and starts a new one, it will send over SMS as expected. However, when Charlie replies to Betty's message, it will be sent over iMessage and won't be received by Alan. Also, once Charlie sends this reply, Betty's thread will switch back over to iMessage, and future messages won't be received by Alan.

The only way to resolve this issue is for Betty and Charlie to both delete their group threads with Alan, and then start a new one.

Configuration:
This issue persists with all devices running the latest version of iOS.