Apple Stops Signing iOS 15.4 Following iOS 15.4.1 Release, Downgrading No Longer Possible

Following the March 31 release of iOS 15.4.1, Apple has stopped signing iOS 15.4, the previously available version of iOS that came out earlier in March. As iOS 15.4 is no longer being signed, it is not possible to downgrade to that version of iOS once you've installed iOS 15.4.1.

iOS 15
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 is no longer being signed.

iOS 15.4 was a major update featuring support for unlocking an iPhone while wearing a mask, new emoji characters, Universal Control on the iPad, and tons more.

iOS 15.4.1 added a fix for a battery drain issue on the ‌iPhone‌, but more importantly, it addressed AppleAVD issue that could allow an application to execute arbitrary code with kernel privileges. Apple said this exploit may have been actively exploited, so it is a good idea to update to iOS 15.4.1 if you have not done so already.

Apple has also stopped signing tvOS 15.4 and HomePod 15.4 software.

Related Forum: iOS 15

Popular Stories

maxresdefault

Apple Shows Off a Key Reason to Upgrade to the iPhone 17

Saturday February 7, 2026 9:26 am PST by
Apple today shared an ad that shows how the upgraded Center Stage front camera on the latest iPhones improves the process of taking a group selfie. "Watch how the new front facing camera on iPhone 17 Pro takes group selfies that automatically expand and rotate as more people come into frame," says Apple. While the ad is focused on the iPhone 17 Pro and iPhone 17 Pro Max, the regular iPhone...
m5 macbook pro deal

Why You Shouldn't Buy the Next MacBook Pro

Tuesday February 10, 2026 4:27 pm PST by
Apple is planning to launch new MacBook Pro models as soon as early March, but if you can, this is one generation you should skip because there's something much better in the works. We're waiting on 14-inch and 16-inch MacBook Pro models with M5 Pro and M5 Max chips, with few changes other than the processor upgrade. There won't be any tweaks to the design or the display, but later this...
iOS 26

Apple Releases iOS 26.3 and iPadOS 26.3

Wednesday February 11, 2026 10:07 am PST by
Apple today released iOS 26.3 and iPadOS 26.3, the latest updates to the iOS 26 and iPadOS 26 operating systems that came out in September. The new software comes almost two months after Apple released iOS 26.2 and iPadOS 26.2. The new software can be downloaded on eligible iPhones and iPads over-the-air by going to Settings > General > Software Update. According to Apple's release notes, ...
apple wallet drivers license feature iPhone 15 pro

Apple Says These 7 U.S. States Plan to Offer iPhone Driver's Licenses

Monday February 9, 2026 6:24 am PST by
In select U.S. states, residents can add their driver's license or state ID to the Apple Wallet app on the iPhone and Apple Watch, and then use it to display proof of identity or age at select airports and businesses, and in select apps. The feature is currently available in 13 U.S. states and Puerto Rico, and it is expected to launch in at least seven more in the future. To set up the...
Apple Logo Zoomed

Apple Expected to Launch These 10+ Products Over the Coming Months

Tuesday February 10, 2026 6:33 am PST by
It has been a slow start to 2026 for Apple product launches, with only a new AirTag and a special Apple Watch band released so far. We are still waiting for MacBook Pro models with M5 Pro and M5 Max chips, the iPhone 17e, a lower-cost MacBook with an iPhone chip, long-rumored updates to the Apple TV and HomePod mini, and much more. Apple is expected to release/update the following products...

Top Rated Comments

Danfango Avatar
50 months ago

Endless updates...more bugs...RedHat 8767092 2000
How dare they inconvenience the user by fixing stuff, protecting the user and improving the product that the user is complaining about!
Score: 8 Votes (Like | Disagree)
vanylapep Avatar
50 months ago
It's a trap.

Once you update your phone to 15.4.1, Xcode 13.2.1 won't allow you to deploy to your phone because it only supports 15.4.0. So you update to Xcode 13.3 but your macOS won't allow it because you're on macOS 11.3 but Xcode 13.3 requires macOS 12.0. So you gota buy a new Macbook.
Score: 7 Votes (Like | Disagree)
Mr. Dee Avatar
50 months ago
I finally upgraded to iOS 15.4.1 from iOS 14.8.1 on my iPhone X and 2017 iPad Pro 12.9. I couldn’t stand the nagging at work anymore. The iPhone X feels like a new phone with the upgrade and I do feel the speed difference. On the iPad there isn’t really not much that feels new but its there. The only other iOS device I have not updated because it failed a couple times is my iPhone 6s.

I took that as a warning sign and leave it be. The watchOS 8.5.1 update failed a couple times, but I just put my S3 next to my X before going to bed and updated the next morning.

So, things are going well otherwise. See you back here next year with iOS 16.
Score: 2 Votes (Like | Disagree)
50 months ago
I'm glad Apple does what it can to stop OS fragmentation.
Score: 2 Votes (Like | Disagree)
winxmac Avatar
50 months ago

I finally upgraded to iOS 15.4.1 from iOS 14.8.1 on my iPhone X and 2017 iPad Pro 12.9. I couldn’t stand the nagging at work anymore. The iPhone X feels like a new phone with the upgrade and I do feel the speed difference. On the iPad there isn’t really not much that feels new but its there. The only other iOS device I have not updated because it failed a couple times is my iPhone 6s.

I took that as a warning sign and leave it be. The watchOS 8.5.1 update failed a couple times, but I just put my S3 next to my X before going to bed and updated the next morning.

So, things are going well otherwise. See you back here next year with iOS 16.
I was on iOS 14.8 then upgraded to iOS 15.4 then I saw that iOS 15.3 RC was still signed at that time so I downgraded to it and still on it at the moment... Upgraded and downgraded using IPSW through iTunes...

In the company I work at, I also receive email notification about needing to go to the latest version otherwise access to company resource will not work... I don't have a work-provided phone and I just decided to upgrade...

Also, note to Apple, re-sign the last update of previous versions so if someone cannot afford to buy a newer model, the device they currently have will still be at least useable although with limited app support...
Score: 2 Votes (Like | Disagree)
50 months ago
When the version that they stop signing has two zero day flaws, there's an inescapable reason to stop letting people downgrade to it.
Score: 2 Votes (Like | Disagree)