How to Downgrade iOS 9.3 Back to iOS 9.2.1
While iOS 9.3 has several new features and is a notable improvement over prior iOS 9.x releases, some users may wish to downgrade iOS 9.3 back to iOS 9.2.1 for whatever reason. Downgrading to the prior release is possible for a limited time, so if you have any interest in doing this you’ll want to move quickly before Apple closes the signing window for the earlier firmware version.