Apple has added a tool its repertoire to attempt to make things right with users leaving the iPhone for other platforms.
For years, registering one’s phone number with iMessage meant that even long after that number was no longer being used on an iPhone, friends and family would still attempt to send it as one. That’s because once Apple registers a phone number in its iMessage database, all other iPhones (with iMessage turned on) think it is an iMessage in order to make the routing invisible to the user.
Unfortunately, that meant that even after turning off iMessage on the user’s side, friends and family’s iPhones would still attempt to send messages as iMessages, either failing or sending the words into the ether. This caused considerable consternation, as Apple essentially “owned” those numbers.
The new iMessage deregistration tool is meant for people that have sold their iPhones without turning off iMessage before resetting their devices.