how to stop "text messaging" for iphone to iphone
I have been imessaging my son for some time, and then it changed to texts (from blue to green). I know this happens sometimes when he's in a spotty area or something, but it usually goes back to blue right away. It's been weeks, and it won't change back. What do I do? I am iPhone 6+, he is iPhone 5C.
iPhone 6 Plus, iOS 8.3