Apple today stopped signing iOS 17.1.1 and iOS 17.1.2, preventing iPhone users from downgrading to those versions of iOS. Apple is no longer signing the updates following the release of iOS 17.2 on December 11 and the launch of iOS 17.2.1 today.

It is not unusual that iOS 17.1.1 and iOS 17.1.2 are no longer being signed. Apple routinely stops signing older versions of iOS after new releases in order to encourage customers to keep their operating systems up to date and to prevent users from downgrading to older, less secure versions of the software.

iOS 17.2.1 is the current version of iOS 17 that is available to the public. It introduced unspecified bug fixes, but the iOS 17.2 update that preceded it brought the Journal app, spatial video recording on the iPhone 15 Pro models, updates to Messages and Apple Music, and more.

Apple is also testing iOS 17.3, an update that is expected to come out in January.

Source: Macrumors