A little more than a week after it released iOS 9.1 to the public, Apple today has stopped signing iOS 9.0.2. This means that users are no longer able to downgrade from iOS 9.1 to iOS 9.0.2, which was initially released almost exactly a month ago.
For Apple, it’s normal for the company to stop signing an older version of iOS when it releases an update to the public. In Apple’s eyes, any bugs that were present in iOS 9.0.2 have since been fixed with iOS 9.1, making it the more stable and secure option for the average user.
Of course, the more likely reason for Apple to stop singing iOS 9.0.2 is to block the hole that the Pangu jailbreak solution circumvents. Pangu released its iOS 9, iOS 9.0.1, and iOS 9.0.2 jailbreak tool two weeks ago. Apple has always attempted to block jailbreak tools and to stop signing older versions of its operating system is the easiest and most basic method of doing so.
The release of iOS 9.1 last week brought about a handful of changes and enhancements, most notably of which included more than 150 new emoji characters. Other changes included new wallpapers, Live Photos enhancements for iPhone 6s and iPhone 6s Plus users, and various other tweaks.
Now that Apple has shut the door on iOS 9.0.2, released iOS 9.1, it is now shifting its focus to iOS 9.2. We should expect a developer beta of it soon.