You Can't Downgrade to iOS 10.2
If you can't stand the iPhone 7 iOS 10.2.1 update's performance, know that you're stuck. You can no longer downgrade to an older version of iOS 10.
Apple has stopped signing off on the iOS 10.2 update which means you can't use a loophole to drop back down to the update. The company isn't signing off on anything older than iOS 10.2 either.
This change is permanent. Apple won't bring back the iOS 10.2 downgrade which means you're stuck on iOS 10.2.1 unless you decide to download the iOS 10.3 beta.
If you think you might want to take advantage of the downgrade process in the future, take a look at our walkthrough.