iOS 26.4 No Longer Signed by Apple, Blocking Downgrades From iOS 26.4.1
Apple today stopped signing iOS 26.4, so iPhone users who have updated to iOS 26.4.1 are no longer able to downgrade to the earlier version of iOS. iOS 26.4.1 came out a week ago.

When software is "signed," it means it can pass the server-side verification check that Apple does when a user downloads a new version of iOS on an iPhone. An update that's not signed can't be installed because it won't pass the verification check.
Apple does not show users earlier versions of iOS after an upgrade has been released, but when software is still signed, it is possible to downgrade with the macOS Finder app on a Mac or the Apple Devices app on a Windows PC.
Unsigning software prevents Apple customers from installing outdated, less secure versions of iOS, and Apple typically stops signing an update a week or so after new software comes out.
iOS 26.4.1 fixed iCloud syncing issues and Stolen Device Protection on enterprise devices. While iOS 26.4.1 is the current publicly available version of iOS, Apple is also beta testing an iOS 26.5 update.
Popular Stories
Apple today released iOS 26.6.2 with a fix for "an issue that prevents downloading a software update over a cellular connection."
The minor software update is rolling out now for the iPhone 11 series and newer. To update your iPhone, open the Settings app and tap on General → Software Update. It might take a few minutes for the update to be visible to everyone.
iOS 26.6.2 arrives...
Apple today released iOS 26.6.1, iPadOS 26.6.1, visionOS 26.6.1, and macOS 26.6.2, with all of the updates containing security fixes.
Apple also released iOS 18.7.10 and iPadOS 18.7.10 with security fixes.
All of the iOS and iPadOS updates released today deliver security fixes that were first made available in the iOS 27 and iPadOS 27 betas, according to an Apple support document, which...
The iOS 26.6.1, iPadOS 26.6.1, and macOS Tahoe 26.6.2 updates Apple released today fix almost 30 security vulnerabilities, according to Apple's security support document. This is Apple's third security release in three weeks as AI surfaces bugs faster than the company's typical release schedule can absorb.
Apple says the software includes security fixes that were previously added to the iOS...