Apple unsigns iOS 13.1.2 and 13.1.3, thwarting downgrades from 13.2

Apple closed the signing window for two different iOS versions for various handsets Wednesday evening, including 13.1.2 and 13.1.3.

It’s regular practice for Apple to stop signing older versions of iOS after a newer release has been available for some time. Doing so both prevents software downgrades by the jailbreak-savvy and encourages software updates for everyone else to ensure users take advantage of the latest features and security patches.

While this might seem like another day in Apple’s walled garden for most, the bigger question here is how this change might impact the jailbreak community, and that’s why we’re about to lay it all out for everyone.

At the time of this writing, no public jailbreak can liberate any firmware newer than iOS 12.4, but there are implications for those using iOS 12.4.1-13.1.3 because a recent software bug exposed by security researcher @S0rryMyBad could potentially result in a tfp0 exploit, which would result in jailbreakability. That said, those who didn’t heed Pwn20wnd’s recent advice to downgrade to supported firmware might be stymied.

…Or perhaps not?

Those with A5-A11 devices will be happy to know that security researcher @axi0mX recently released a compatible bootrom exploit called checkm8, and this is huge because a bootrom exploit targets hardware and can’t be patched with a software update. With that in mind, even iOS 13.2 (the latest release as of now) can be pwned on handsets as recent as the iPhone X, and hacker Luca Todesco (along with others) are already working on a jailbreak tool that supports it dubbed checkra1n.

TL;DR, Apple’s decision to stop signing iOS 13.1.3 and some older versions really doesn’t impact potential jailbreakers unless they’re sporting A12(X) or A13 devices. Even then, those who managed to downgrade when they had the chance won’t be compelled to upgrade unless they try to restore their device.

Apart from jailbreaking, there aren’t many reasons to downgrade one’s iPhone or iPad firmware. The lone exception might be when Apple introduces a software update that breaks something or causes issues, and that’s very well the case with iOS 13.2, which evidently caused application memory issues for backgrounded tasks. The new iOS 13.3 beta is said to fix this, but the software update isn’t available to the masses yet. Unfortunately, the only way to circumvent this issue would have been downgrading, which is no longer possible as of this evening.

As always, you can check to see what versions of iOS are and aren’t being signed at, a handy utility for investigating such things. Please note that it may take some time before the website updates for all hardware and software combinations.

Are you upset to see these firmware versions unsigned, or are you happily using the latest iOS release on your daily driver handset already? Discuss your circumstances in the comments section.