Apple Stops Signing iOS 15.3.1 Following iOS 15.4 Release, Downgrading No Longer Possible

Following the release of iOS 15.4 on March 14, Apple has stopped signing iOS 15.3.1, the previously available version of iOS that came out in February. As iOS 15.3.1 is no longer being signed, it is not possible to downgrade to that version of iOS if you've updated to iOS 15.4.

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 15.3.1 is no longer being signed.

iOS 15.3.1 was a bug fix update that addressed WebKit vulnerabilities, while iOS 15.4 was a major update that added new emoji characters, Face ID with a mask support, and tons of other features. Apple has also stopped signing tvOS 15.3.

Popular Stories

Alleged iPhone 17 Pro Antenna Design

Two All-New iPhone 17 Colors Seemingly Confirmed

Monday August 25, 2025 4:22 am PDT by
Apple will offer the upcoming iPhone 17 Pro and iPhone 17 Pro Max in a new orange color, according to Bloomberg's Mark Gurman. Gurman made the claim in the latest edition of his Power On newsletter, adding that the new iPhone 17 Air – replacing the iPhone 16 Plus – will come in a new light blue color. We've heard multiple rumors about a new iPhone 17 Pro color being a shade of orange. The ...
AirPods Pro 3 Heart Rate Tracking Feature

AirPods Pro 3 Expected to Launch This Year With Key New Feature

Sunday August 24, 2025 7:16 am PDT by
Bloomberg's Mark Gurman expects Apple to release new AirPods Pro this year, and he said the earbuds will have a key new feature: heart rate monitoring. From his Power On newsletter today, with emphasis added:As for Apple's other devices, there's a lot in the fall pipeline — though many of the new products are only incremental upgrades. There will be Apple Watch updates, faster Vision...
iPhone 17 Pro on Desk Centered 1

iPhone 17 Pro Coming Soon With These 12 New Features

Sunday August 24, 2025 6:00 am PDT by
Apple's iPhone 17 Pro and iPhone 17 Pro Max should be unveiled in a few more weeks, and there are plenty of rumors about the devices. In his Power On newsletter today, Bloomberg's Mark Gurman corroborated a rumor that iPhone 17 Pro models will be "available in an orange color." Below, we recap key changes rumored for the iPhone 17 Pro models: Aluminum frame: iPhone 17 Pro models are...
iPhone 17 Air Thumb 2 Blue Electric Boogaloo

Apple Has Reportedly Considered Releasing iPhone 17 Air Bumper Case

Sunday August 24, 2025 12:40 pm PDT by
Apple has "considered" releasing a bumper case for the upcoming iPhone 17 Air, according to Bloomberg's Mark Gurman. Similar to the bumper case that Apple introduced for the iPhone 4 in 2010, Gurman said the iPhone 17 Air version of the case would cover the edges of the device, but not the back of it. Those bumper cases were made of rubber. Given that the iPhone 17 Air is expected to have ...
awe dropping event

Apple Event Announced for September 9: 'Awe Dropping'

Tuesday August 26, 2025 9:01 am PDT by
Apple will hold its annual iPhone-centric event on Tuesday, September 9 at the Apple Park campus in Cupertino, California, according to an announcement that went out today. The event will start at 10:00 a.m., with select members of the media invited to attend. At the September 2025 iPhone event, Apple will unveil the iPhone 17 lineup, which includes an all-new ultra-thin iPhone 17 Air. It...
Awe Dropping Apple Event Feature

Five Things to Expect From Apple's 'Awe Dropping' September 9 Event

Tuesday August 26, 2025 4:17 pm PDT by
Apple today announced its "Awe Dropping" iPhone-centric event, which is set to take place on Tuesday, September 9 at 10:00 a.m. Pacific Time. There are a long list of products that are coming, but we thought we'd pull out five feature highlights to look forward to. That Super Thin iPhone - Apple's September 9 event will see the unveiling of the first redesigned iPhone we've had in years, ...
airpods pro 2 gradient

AirPods Pro 3: Four Key Design Changes Anticipated

Tuesday August 26, 2025 4:05 am PDT by
Apple hasn't updated the AirPods Pro since 2022 other than a shift from Lightning to USB-C, and the earbuds are due for a refresh. According to Bloomberg's Mark Gurman, Apple will launch AirPods Pro 3 later this year, and apart from new features like heart rate monitoring, we're also expecting a few design changes. The fourth‑generation AirPods offer useful clues to Apple's design cues for ...
Awe Dropping Apple Event Feature

Apple Event Logo Hints at Two iPhone 17 Pro Features

Wednesday August 27, 2025 6:36 am PDT by
Apple's logo for its upcoming September 9 event hints at two rumored iPhone 17 Pro features, including new color options and a vapor chamber cooling system. Of course, this is all just speculation for fun, as we count down the final days until the event. New Colors Last month, Macworld's Filipe Espósito reported that orange and dark blue would be two out of the five color options...

Top Rated Comments

Black Magic Avatar
45 months ago

I'm still on iOS 14, but it looks like I need to upgrade since a policy at work requires I am on iOS 15 in order to use the internal Wi-Fi. I am going to try to hold out for iOS 15.5.1 though.
You holding out for what? You denying yourself great features thinking you are saving yourself from bugs and headaches? You like 2 years behind the curve and you feel like that is something to brag about?
Score: 9 Votes (Like | Disagree)
Y014951 Avatar
45 months ago

What features am I missing out on exactly that are so detrimental? I have been doing this every year since iOS 11. At the end of the day, it’s about the apps. iOS is just an OS. Most of what I already need in terms of integration doesn’t require iOS 15.
I honestly don't understand the downvotes. Mr. Dee seems to be a quite active participant in the Macrumors forums so I believe he knows what features he's missing. It's his decision to update his devices (or not) after all...
Score: 7 Votes (Like | Disagree)
Black Magic Avatar
45 months ago

What features am I missing out on exactly that are so detrimental? I have been doing this every year since iOS 11. At the end of the day, it’s about the apps. iOS is just an OS. Most of what I already need in terms of integration doesn’t require iOS 15.
Your employer is trying to nudge you into the present. You are obviously missing the point.
Score: 5 Votes (Like | Disagree)
now i see it Avatar
45 months ago
and good riddance
Score: 4 Votes (Like | Disagree)
canadianreader Avatar
45 months ago
We need the right to downgrade. I hope sideloading will open that door.
Score: 4 Votes (Like | Disagree)
Mr. Dee Avatar
45 months ago

Your employer is trying to nudge you into the present. You are obviously missing the point.
The same employer who has Windows 7 clients all over its network?
Score: 3 Votes (Like | Disagree)