Apple Stops Signing iOS 15.4.1 Following iOS 15.5 Release, Downgrading No Longer Possible
Following the May 16 launch of iOS 15.5, Apple has stopped signing iOS 15.4.1, the previously available version of iOS that came out in late March. Because iOS 15.4.1 is no longer being signed, it is not possible to downgrade to that version of iOS after installing iOS 15.5.

Apple routinely stops signing older versions of software updates after new releases come out in order to encourage customers to keep their operating systems up to date, so it is not unusual that iOS 15.4.1 is no longer being signed.
iOS 15.4.1 was a minor update that addressed an issue that could cause the iPhone's battery to drain more quickly following the iOS 15.4 launch. It also addressed an AppleAVD issue that could allow an application to execute arbitrary code with kernel privileges, which Apple said was actively exploited.
iOS 15.5 added an Apple Cash feature for requesting and sending money, along with new features for Podcasts and a fix for an issue with home automations. It also included several security updates, and those who have not already upgraded to iOS 15.5 should do so for that reason.
Popular Stories
Update 10:04 a.m.: iOS 27 is rolling out now, though it may take a bit for all users to see it, so keep checking!
Apple is about to release iOS 27, which will finally deliver more advanced Siri AI capabilities as well as a variety of other refinements, improvements, and new features to iPhones. It's Apple's biggest software update of the year, and Apple announced at Wednesday's iPhone event...
Update: Apple has released iOS 27.
During its iPhone 18 Pro and iPhone Duo event last week, Apple announced that iOS 27 will be released widely on Monday, September 14.
iOS 27 should be available around 10 a.m. Pacific Time / 1 p.m. Eastern Time today via the Settings app, under General → Software Update.
Below, we have highlighted eight new features and changes coming with iOS...
As noted by Nicolas Lellouche, who writes for the French tech website Numerama, Apple has updated its tech specs pages for the iPhone 18 Pro and iPhone 18 Pro Max to clarify which models are equipped with its new C2 cellular modem and where.
Apple now says the iPhone 18 Pro has a C2 modem worldwide, while the iPhone 18 Pro Max uses the chip in every country except for the U.S.
According...