T-Mobile first in U.S. to allow iPhone users with iOS 9 beta to employ Continuity over cellular12
But iOS 9 is going to allow those with Apple devices to use Continuity over cellular. T-Mobile subscribers are the first to have the ability to use this new feature. If you have the iOS 9 beta installed, you can switch devices to continue texts and phone conversations, even if the iPhone and iPad being used are not on a Wi-Fi pipeline. Eventually, this will be available for customers of most (if not all) carriers.
Again, Continuity over cellular is coming to iOS 9. If Continuity is a feature you use often and you want to cut the Wi-Fi strings that hold you back, you might want to install the preview version of the iOS 9 beta so that you can use Continuity over a cellular connection right now. Keep in mind that currently, this is available only for T-Mobile subscribers.