First reported by 9to5mac, the change can be confirmed on the third-party iOS firmware database IPSW Downloads. It points out that iOS 8.1.1 is "now the earliest software version that devices can be restored to." The IPSW Downloads page for iOS 8.1 now shows a red "!" icon replacing the green check mark.
Apple started rolling out the iOS 8.1.1 update last month and included miscellaneous bug fixes and security updates, with iPhone 4S and iPad 2 - two devices that bore the brunt of the iOS 8 update in terms of slowdown in performance - especially called out in the release notes. The iOS 8.1.1 update is available for the iPhone 4S and later models, the iPad 2 and later models, the fifth-generation iPod touch, and the third-generation Apple TV.
The Cupertino-based giant back in October rolled out the iOS 8.1 update bringing features such as Apple Pay (only for iPhone 6 and iPhone 6 Plus), iCloud Photo Library beta, Camera Roll, Continuity and more.
Apple last week revealed that iOS 8 is now present on 60 percent of active iOS devices. The official App Store Distribution page confirmed that the majority (60 percent) of active iOS devices are running iOS 8, followed by 35 percent still running iOS 7, and 5 percent still running earlier versions.