Apple Stops Signing iOS 13.3.1 Following Release of iOS 13.4

IPSWFollowing the release of iOS 13.4 on March 24, Apple has stopped signing iOS 13.3.1, which means downgrading to that version of iOS is no longer possible.

iOS 13.3.1 was a minor update that added a toggle for disabling the U1 chip in Apple's iPhone 11, 11 Pro, and 11 Pro Max.

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.

iOS 13.4 is the current publicly available version of iOS, with the update bringing a new Mail toolbar, iCloud Folder Sharing, new Memoji stickers, trackpad support on iPad, and more.

Developers can also download iOS 13.4.5, an upcoming update with bug fixes and a new option to share Apple Music songs on Instagram Stories.

Popular Stories

iOS 26

iOS 26.3 and iOS 26.4 Will Add These New Features to Your iPhone

Tuesday February 3, 2026 7:47 am PST by
We are still waiting for the iOS 26.3 Release Candidate to come out, so the first iOS 26.4 beta is likely still at least a week or two away. Following beta testing, iOS 26.4 will likely be released to the general public in March or April. Below, we have recapped known or rumored iOS 26.3 and iOS 26.4 features so far. iOS 26.3 iPhone to Android Transfer Tool iOS 26.3 makes it easier...
Apple Logo Black

Apple's Next Launch is 'Imminent'

Sunday February 1, 2026 12:31 pm PST by
The calendar has turned to February, and a new report indicates that Apple's next product launch is "imminent," in the form of new MacBook Pro models. "All signs point to an imminent launch of next-generation MacBook Pros that retain the current form factor but deliver faster chips," Bloomberg's Mark Gurman said on Sunday. "I'm told the new models — code-named J714 and J716 — are slated...
iOS 26 Home Feature

Apple Gives Final Warning to Home App Users

Tuesday February 3, 2026 8:55 am PST by
In 2022, Apple introduced a new Apple Home architecture that is "more reliable and efficient," and the deadline to upgrade and avoid issues is fast approaching. In an email this week, Apple gave customers a final reminder to upgrade their Home app by February 10, 2026. Apple says users who do not upgrade may experience issues with accessories and automations, or lose access to their smart...
Aston Martin CarPlay Ultra Screen

Apple's CarPlay Ultra to Expand to These Vehicle Brands Later This Year

Sunday February 1, 2026 10:08 am PST by
Last year, Apple launched CarPlay Ultra, the long-awaited next-generation version of its CarPlay software system for vehicles. Nearly nine months later, CarPlay Ultra is still limited to Aston Martin's latest luxury vehicles, but that should change fairly soon. In May 2025, Apple said many other vehicle brands planned to offer CarPlay Ultra, including Hyundai, Kia, and Genesis. In his Powe...
Apple Foldable Thumb

First Foldable iPhone Design Details Revealed

Monday February 2, 2026 7:19 am PST by
Apple's first foldable iPhone will feature relocated volume buttons, an all-black camera plateau, a smaller Dynamic Island, and more, according to design leaks from a known Weibo leaker. The user known as "Instant Digital" today claimed to share several key details about the design of the foldable iPhone: The volume buttons will be located on the top edge of the device, aligned to the...

Top Rated Comments

JosephAW Avatar
76 months ago
Still happily on iOS 12.4.1. Every time I think of upgrading I read all kinds of horror stories with email and crashing and the such. Maybe iOS 14 will be better. Not likely though. I think each iteration is progressively getting worse. iOS 8 was my favorite then iOS 10.
Score: 4 Votes (Like | Disagree)
calzon65 Avatar
76 months ago
I have always hated Apple's pathetic "no downgrade" policy. There are countless stories of people upgrading then discovering weeks later the upgrade broke something. I don't care what Apple's reasons are, this is and has been a terrible policy for consumers. :mad:
Score: 4 Votes (Like | Disagree)
MattMJB0188 Avatar
76 months ago
They stopped signing 13.3.1 and I'm still on 12.4 lol. I get much better performance on my 8 Plus than 13.4.
Score: 4 Votes (Like | Disagree)
Pakaku Avatar
76 months ago
The fact that Apple refuses to let people downgrade their iOS versions will always be one of the many reasons I can never consider iOS devices to be "real" computers
Score: 3 Votes (Like | Disagree)
Villarrealadrian Avatar
76 months ago
This should be illegal...
Score: 2 Votes (Like | Disagree)
mdorais Avatar
76 months ago

I have always hated Apple's pathetic "no downgrade" policy. There are countless stories of people upgrading then discovering weeks later the upgrade broke something. I don't care what Apple's reasons are, this is and has been a terrible policy for consumers. :mad:
Agreed. They broke playing homemade mp4's so now I can't watch them anymore on my iPad. Only Apple purchased movies work now. Wish I could down downgrade because I gained nothing useful but lost a major function by upgrading.
Score: 1 Votes (Like | Disagree)