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

Apple iPhone 16e Feature

Apple Announces iPhone 16e With A18 Chip and Apple Intelligence, Pricing Starts at $599

Wednesday February 19, 2025 8:02 am PST by
Apple today introduced the iPhone 16e, its newest entry-level smartphone. The device succeeds the third-generation iPhone SE, which has now been discontinued. The iPhone 16e features a larger 6.1-inch OLED display, up from a 4.7-inch LCD on the iPhone SE. The display has a notch for Face ID, and this means that Apple no longer sells any iPhones with a Touch ID fingerprint button, marking the ...
iphone 17 pro asherdipps

iPhone 17 Pro Models Rumored to Feature Aluminum Frame Instead of Titanium Frame

Tuesday February 18, 2025 12:02 pm PST by
Over the years, Apple has switched from an aluminum frame to a stainless steel frame to a titanium frame for its highest-end iPhones. And now, it has been rumored that Apple will go back to using aluminum for three out of four iPhone 17 models. In an investor note with research firm GF Securities, obtained by MacRumors this week, Apple supply chain analyst Jeff Pu said the iPhone 17, iPhone...
apple launch feb 2025 alt

Here Are the New Apple Products We're Still Expecting This Spring

Thursday February 20, 2025 5:06 am PST by
Now that Apple has announced its new more affordable iPhone 16e, our thoughts turn to what else we are expecting from the company this spring. There are three product categories that we are definitely expecting to get upgraded before spring has ended. Keep reading to learn what they are. If we're lucky, Apple might make a surprise announcement about a completely new product category. M4...
Generic iOS 18

Here's When Apple Will Release iOS 18.4

Wednesday February 19, 2025 11:38 am PST by
Following the launch of the iPhone 16e, Apple updated its iOS 18, iPadOS 18, and macOS Sequoia pages to give a narrower timeline on when the next updates are set to launch. All three pages now state that new Apple Intelligence features and languages will launch in early April, an update from the more broader April timeframe that Apple provided before. The next major point updates will be iOS ...
apple launch feb 2025

Tim Cook Teases an 'Apple Launch' Next Wednesday

Thursday February 13, 2025 8:07 am PST by
In a social media post today, Apple CEO Tim Cook teased an upcoming "launch" of some kind scheduled for Wednesday, February 19. "Get ready to meet the newest member of the family," he said, with an #AppleLaunch hashtag. The post includes a short video with an animated Apple logo inside a circle. Cook did not provide an exact time for the launch, or share any other specific details, so...
prioritize notifications ios 18 4

Everything New in iOS 18.4 Beta 1

Friday February 21, 2025 1:08 pm PST by
Apple finally released the first beta of iOS 18.4 to developers for testing purposes, and while the beta is lacking some of the Apple Intelligence features we were hoping for, there are some notable new additions. Subscribe to the MacRumors YouTube channel for more videos. Priority Notifications - Apple Intelligence There is a new Priority Notifications feature that can show you your most...
apple c1

Apple Unveils 'C1' as First Custom Cellular Modem

Wednesday February 19, 2025 8:08 am PST by
Apple today announced its first custom cellular modem with the name "C1," debuting in the all-new iPhone 16e. The new modem contributes to the iPhone 16e's power efficiency, giving it the longest battery life of any iPhone with a 6.1-inch display, such as the iPhone 15 and iPhone 16. Expanding the benefits of Apple silicon, C1 is the first modem designed by Apple and the most...

Top Rated Comments

Danfango Avatar
38 months ago

Endless updates...more bugs...RedHat LinMac 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
38 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
38 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)
_Spinn_ Avatar
38 months ago
I'm glad Apple does what it can to stop OS fragmentation.
Score: 2 Votes (Like | Disagree)
winxmac Avatar
38 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)
leicaman Avatar
38 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)