If you're switching away from iPhone to Android or something else, turn off iMessage to make sure you don't miss a text.

The Messages app lets your iPhone and iPad owning friends, family, and colleagues send you iMessages instead of SMS or MMS, thus avoiding carrier fees. Apple does this by detecting that you're both using iOS and then sending an iMessage instead of an SMS or MMS. If you stop using your iPhone, though, and switch to Android, Apple has to stop sending iMessages instead of SMS. The best way to make sure Apple knows you've switched, and to make sure you don't miss any messages from those still using iOS, is to turn off iMessage before you go.

How to deactivate iMessage before switching from iPhone to Android, BlackBerry, or Windows Phone

Complete these steps from your iPhone before starting to use your new smartphone:

  1. Launch Settings from the Home screen of your iPhone.
  2. Tap Messages.
  3. Tap the slider next to iMessage to turn it off.

    Launch Settings, tap Messages, disable iMessage

  4. Go back to Settings.

  5. Tap on Facetime.
  6. Tap the slider next to Facetime to turn it off.

Now hop into the Messages app and send some messages to people you know have iPhones to make sure they can message you back. You want green messages bubbles for everything.

Once you're done this, iMessage should deactivate from Apple's servers and you shouldn't have any issues, nor should you have to go any further into this guide. As a side note, the sooner you do this, the better off you are. If you know you're going out to purchase an Android, BlackBerry, or Windows Phone in 3 days, do this process right now. That way you have turned off iMessage and it gives the servers a few days to actually process the request completely and boot you off.

Once you've switched to your new smartphone, verify you can send and receive text messages to someone else using an iPhone. If you aren't receiving anything back, continue on to remedy the problem...

How to manually deactivate iMessage from Apple's servers

If you've already migrated over to your new device but forgot to deactivate iMessage and no longer have access to an iPhone, don't sweat. Apple has an online process for you to deactivate your phone number from the iMessage servers.

  1. Go to (http://selfsolve.apple.com/deregister-imessage) from any web browser.
  2. Scroll down to the second section labeled No longer have your iPhone?.
  3. Enter the phone number you'd like to de-activate from iMessage and click Send Code.
  4. Check your current phone for a text message and enter the code that you're sent.
  5. Wait for confirmation that iMessage has been de-activated.

Alternatively, you can need to call 1-800-MY-APPLE in order to have Apple manually de-register your phone number from the Apple servers. In order to do this, make sure you have your Apple ID on hand as well as the phone number in question.

To expedite the process of your call, be sure to ask for technical support when calling in. Then just tell them you're switching to a smartphone that isn't an iPhone and you can't receive messages so you need them to manually unregister you from the iMessage servers.