Apple Stops Signing iOS 17.2.1, Downgrading No Longer Possible - MacRumors
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Apple Stops Signing iOS 17.2.1, Downgrading No Longer Possible

Apple today stopped signing the iOS 17.2.1 update, preventing iPhone users from downgrading to that version of iOS going forward. iOS 17.2.1 is no longer being signed following the January 22 release of iOS 17.3, which introduced Stolen Device Protection for the iPhone and other changes.

iOS 17
It is not unusual that iOS 17.2.1 is no longer being signed. Apple routinely stops signing older versions of iOS after new releases in order to encourage customers to keep their operating systems up to date and to prevent users from downgrading to older, less secure versions of the iPhone operating system.

Along with iOS 17.2.1, Apple has stopped signing iPadOS 17.2 for the iPad, and the older 15.8 and 16.7.4 versions of iOS and iPadOS for devices unable to run iOS 17.

Apple is already testing iOS 17.4, a major update that is set to come out in March.

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Top Rated Comments

34 months ago

Ive never downgraded ios… i wonder what percentage of users do…
Almost no one
Score: 5 Votes (Like | Disagree)
Populus Avatar
34 months ago
I would have liked to install iOS/iPadOS 16.7.4 on my devices, but… my devices are able to run iOS/iPadOS 17, so Apple didn’t allow me to install those iOS/iPadOS 16 patched versions.
Score: 4 Votes (Like | Disagree)
34 months ago

Ive never downgraded ios… i wonder what percentage of users do…
No one does, and I have no idea why Macrumors runs these articles as if its some kind of important PSA. No one cares. No one should care.
Score: 3 Votes (Like | Disagree)
CheffyDude Avatar
34 months ago
Why not? We should be able to run whatever version of iOS we want.
Score: 3 Votes (Like | Disagree)
CheffyDude Avatar
34 months ago

what if someone wanted to run a 12 year old version of iOS? Are the developers supposed to just perpetually provide security updates for prehistoric versions of iOS that are no longer optimized and lack several features?
Yes.
Score: 2 Votes (Like | Disagree)
34 months ago
Ive never downgraded ios… i wonder what percentage of users do…
Most users don’t. The biggest issue is for developers and development. The lack of signing older OS makes non upgraded phones and iPads very valuable as that is the only way to test on older os’s on physical devices.

General rule is app support 2 major versions so say we have a crash reports coming in from iOS 16. Testing on a physical iOS 16 device is very valuable. There are a lot of issues that only happen and can replicate on a physical device hence older OS are important.

It is developers that the lack of downgrading screws and it will make older non upgraded devices very valuable and we will murder someone who upgrades a test device that was set aside to not upgrade.
Score: 1 Votes (Like | Disagree)