Following the release of iOS 10.2 last week, Apple this evening has stopped signing iOS 10.1 and iOS 10.1.1 for all devices. This means that users are now longer able to downgrade to the operating system if they are having some sort of issue with the latest iOS 10.2 release.
Generally, Apple stops signing older iOS releases to prevent users from downgrading and being vulnerable to security holes that have since been patched. This primarily affects jailbreak users the most, but there was never a jailbreak available for iOS 10.1 or iOS 10.1.1.
Because Apple has stopped signing the two operating systems, users will no longer be able to downgrade to the operating system after updating to iOS 10.2. This means that once you update, you’re permanently committed to the new version.
Apple last week released iOS 10.2 with new emoji and Messages effects, an all-new TV app, new wallpapers, and more. The company also released the second beta of iOS 10.2.1 earlier today, which includes bug fixes and performance improvements.