Apple Stops Signing iOS 11.2.5 Firmware Killing Downgrades from iOS 11.2.6
If you planned on downgrading your iPhone, iPad or iPod touch device to iOS 11.2.5, you should know that Apple recently stopped signing the firmware, which means you’re now stuck with iOS 11.2.6, the latest stable version.
If you’re running the latest iOS 11.2.6 software update on your iPhone, iPad, or iPod touch device, you will no longer be able to downgrade it to a previous iOS version, such as iOS 11.2.5, as Apple stopped signing the firmware on March 1st, 2018.
Of course, if you’re using an iOS version prior to iOS 11.2.5, such as iOS 11.2.2 or earlier, you won’t be able to upgrade to iOS 11.2.5 either. Instead, you’ll have to upgrade directly to iOS 11.2.6, which is currently the only stable iOS software offered by Apple.