On Monday, Apple has stopped signing some iOS 9.3 firmware files — preventing users from downgrading from iOS 9.3.1 and above. The move comes less than three weeks after iOS 9.3.1 was released to the public.
As a result, downgrades through iTunes to iOS 9.3 are no longer possible, and there’s no way to upgrade specifically to iOS 9.3 from an earlier firmware. Instead, users will be directed to install iOS 9.3.1 when restoring or updating their devices through iTunes.
IPSW.me, a website that provides real-time signing status for Apple’s firmware files, confirms that iOS 9.3 for most devices is no longer being signed. This means that attempting to downgrade to it from a more recent release will simply throw up an error. Apple is still signing new builds for some of the older devices, which were released to fix the Activation Lock bug.
It is not a major issue for jailbreakers as it was not possible to jailbreak iOS 9.3. Downgrading can be useful in cases where the previous iOS software update can be jailbroken. So it would have been quite useful if it was possible to downgrade to iOS 9.1, which can be jailbroken using Pangu Jailbreak. Some users also prefer to downgrade back to the older version if they face problems after upgrading to the latest iOS software update.
This doesn’t come as a surprise, as over the last few years, Apple has used this strategy to keep jailbreakers at bay. It not only releases new software updates, that fixes the vulnerabilities used by the jailbreaks, it also stops signing the older iOS firmware file, which prevents users from downgrading back to the older iOS version that can be jailbroken.
It goes without saying that given the current situation, jailbreakers should be very careful while installing jailbreak tweaks as a bad tweak could easily force you to restore your device, which would mean that you will lose the jailbreak and all the tweaks installed on your device.
You should also remember that restoring your iOS device will also force an upgrade to iOS 9.3.1, now that iOS 9.3 is not available.