Following a rigorous beta period, Apple unleashed its iOS & iPadOS 15.4 software updates for iPhone and iPad last Monday with huge upgrades, such as being able to unlock an iPhone with Face ID while wearing a mask and support for Universal Control, among other things. As we come up on a full week after the release, it’s unsurprising to see that Apple has now stopped signing the previous release: iOS & iPadOS 15.3.1.
By no longer signing iOS & iPadOS 15.3.1, Apple has effectively stopped most of the general public from being able to downgrade to it from a newer version. This also has the effect of preventing upgrades to iOS & iPadOS 15.3.1 specifically if the user is currently running an older firmware.
Exceptions to the aforementioned changes do exist, such as the DelayOTA method for supervised devices and futurerestore for those devices which have had their .shsh blobs saved for the firmware they wish to upgrade to – assuming those blobs were saved while the firmware was still being signed. At the time of this writing, these are the only two mass means of circumvention to Apple’s signing process.
Despite these exceptions, they require more effort from the end user, and it’s clear from this that Apple wants to deter and disrupt downgrades to spur new software adoption. This not only pleases Apple’s shareholders when the company boasts firmware adoption numbers at special events, but it also limits access to jailbreaks, which tend to target older firmware versions that are more susceptible to kernel exploitation.
In this case, no version of iOS or iPadOS 15 is currently jailbreakable, however a recently-released kernel exploit for iOS & iPadOS 15.0-15.1.1 has raised high hopes that we could see one in the future. Having said that, iOS & iPadOS 15.3.1 isn’t supported by that exploit, so today’s news doesn’t hinder the jailbreak community as much as it would if iOS & iPadOS 15.3.1 were a jailbreakable firmware.
But jailbreaking isn’t the only reason why iPhone and iPad users might want to install unsigned firmware – this can also be an option if and when a new software update breaks native functionality that the user depends on, such as when iOS 14.7 broke the ability to unlock paired Apple Watches with an iPhone’s Touch ID authentication and when iOS & iPadOS 13.2 imposed overly-aggressive app backgrounding management.
In un-signing older firmware, Apple not only harms the jailbreak community, but leaves those in the aforementioned boat in a bad place since they’re forced to wait for Apple to release official fixes in additional software updates. Still, Apple doesn’t see this as a user choice issue; the company prefers taking a ‘we know best’ approach to most software-based decisions.
If you’re ever curious about what firmware is currently being signed for your iPhone or iPad, then the IPSW.me website is a handy resource. You can also use our dedicated Downloads page to download any firmware file you need for your device.
Are you sad to see that Apple has stopped signing iOS & iPadOS 15.3.1? Be sure to let us know in the comments section down below.