Seconded. I still have the old iPhone. I wonder if reregistering and deregistering with the new tool will help or just make things worse.

This is only an issue for me because Apple made the arbitrary decision to make your iPhone functionally useless after a restore unless you insert a SIM. I still use my iPhone for dev. Guess what happened after a restore once I inserted my SIM? My iPhone automatically enrolled my phone number in iMessages. I spent months getting SMS working after switching to Android and I'm back at square one. This is antitrust level BS.

Likewise here - switched from iPhone (on Verizon) to Android (on T-Mobile), and in several group threads I no longer see the replies of some of the participants. Truly frustrating, and makes you feel marginalized from the conversation.