1. After you complete your iOS upgrade, please click on the Settings icon on your screen.
2. Select the Cellular Data Options menu option, located toward the top of the screen.
3. In the Cellular Data Options menu, if not already enabled, enable LTE in the toggle at the top of the screen.
4. In that same menu, select the Cellular Data Network option.
5. Once in the Cellular Data menu, please manually enter the following information:
|MMS Proxy||leave blank|
|MMS Max Message||1048576|
|MMS UA Prof Url||http://www.apple.com/mms/uaprof.rdf|
Once the above settings have been entered, please restart your phone for the changes to take effect.
NOTE: If you do not update your MMS settings after upgrading to iOS10 then you will not be able to send MMS messages. iMessage will still work, but MMS files to people not on iMessage will fail. You will also not get any photo, video, or other MMS files from non-iMessage users.