10 Things to Know About the iPhone 5 iOS 9.2.1 Update

You Can't Downgrade to iOS 9.2

You can no longer downgrade to the iOS 9.2 update.

Apple's no longer signing off on the iOS 9.2 update which means you can't downgrade back to it if the going gets too tough for you and the iPhone 5. 

For the future, know that Apple typically closes off the loophole one to two weeks after an update's release. It did that here with iOS 9.2.