As expected, Apple has stopped signing iOS 11.1.2, just a few days after releasing iOS 11.2.1. This means that users won’t be able to downgrade from iOS 11.2.1 or iOS 11.2 to iOS 11.1.2, and will get Error 3194 – This device isn’t eligible for the requested build if they try to install iOS 11.1.2 using iTunes.
This can be confirmed by visiting ipsw.me, a website that provides real-time signing status for iOS firmware files.
Downgrading can be useful in cases where the previous iOS software update can be jailbroken. With the release of the tpf0 iOS 11.1.2 exploit, and the possibility of an iOS 11.1.2 jailbreak, it would have been quite useful if it was possible to downgrade to iOS 11.1.2. Some users also prefer to downgrade back to the older version if they face problems after upgrading to the latest iOS software update. Apple has also stopped signing iOS 11.1.1 along with iOS 11.1.2.
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.
Security researchers have successfully jailbroken iPhone X on iOS 11.2.1, but they have said that they don’t plan to release a jailbreak. So it remains to be seen if someone in the jailbreak community is able to discover the exploits and release the much-awaited iOS 11 jailbreak. If you’re on iOS 11.1.2 or lower then it is always advisable to avoid updating to the latest iOS version, to increase your chances of a jailbreak.