Apple officially stopped signing iOS and iPadOS 13.3.1 Tuesday evening, just one week after releasing iOS and iPadOS 13.4 to the general public as an over-the-air software update.

The closing of the signing window means those who’ve upgraded to the newer 13.4 firmware will be unable to downgrade to 13.3.1. This isn’t a big deal for most iPhone or iPad users, but it’s something that can be particularly unsettling for the jailbreak community as software updates frequently patch jailbreak-centric software exploits.

In this particular instance, iOS 13.3.1 could only be jailbroken on A7-A11 devices via the bootrom exploit-based checkra1n jailbreak tool. Those using newer handsets, however, could only jailbreak up to iOS 13.0 via the unc0ver jailbreak tool, and perhaps soon the Chimera13 jailbreak tool.

More recently, a kernel bug exploit proof-of-concept encompassing iOS 13.3.1 had been teased, but it remains to be seen if team unc0ver can take advantage of it in any way. Not that it matters for those who’ve upgraded to iOS 13.4 already, but those on iOS 13.3.1 with any intention of jailbreaking are advised to stay on their current firmware rather than upgrading until we know for sure what’s going to happen.

Jailbreaking aside, there are legitimate reasons to downgrade your firmware even if you don’t want to hack your iOS device. One example would be when a software upgrade introduces a bug that interferes with your workflow, and sometimes downgrading can provide temporary relief until Apple launches another update to resolve the issue.

Apple has a responsibility to keep its users safe from hackers, so it’s understandable that the company would want its users using the latest version of iOS as opposed to downgrading to older versions. Un-signing older software versions of iOS is just one way to facilitate upgrades, voluntary or not. This is unfortunate for jailbreaking, but generally positive for the bulk of Apple’s user base.

As always, you can see what firmware versions are being signed for your iPhone or iPad with the handy IPSW.me online utility.

Source: iDB