Apple has added a page to its website for deregistering and turning off iMessage for users that have switched from an iPhone to an Android device or other non-Apple smartphone. The new web-based tool arrives after Apple faced a lawsuit over Android users having undelivered text messages from other iPhone, iPad and iPod touch users still using iMessage.
For those that have switched to another smartphone and no longer own an iPhone, the website provides a field where you can enter your phone number, receive a confirmation code and enter that code to confirm your iMessage deregistration. Apple also reiterates instructions on how to deregister and turn off iMessage if you still have an iPhone.
The step-by-step instructions for those that still have an iPhone are as follows: transfer your SIM card to your iPhone, open Settings, tap on Messages and turn off iMessage using the toggle switch. If you are still dealing with undelivered text messages after following those steps, Apple has also added a support page for deregistering iMessage.