Apple today stopped signing iOS 17.3.1 preventing iPhone users from downgrading to that version of iOS. iOS 17.3.1 is no longer being signed following the March 5 release of iOS 17.4, an update that introduced app ecosystem changes in the EU, new emoji, and more.
Apple routinely stops signing older versions of iOS, so it is not unusual that the iOS 17.3.1 update is no longer available. Apple prevents users from installing older versions of iOS to encourage customers to keep their operating systems up to date and to prevent downgrading to older, less secure versions of the iPhone operating system.
iOS 17.4 is now the only publicly released version of iOS available. This article, "Apple Stops Signing iOS 17.3.1, Downgrading No Longer Available" first appeared on MacRumors.comDiscuss this article in our forums