Apple Stops Signing iOS 15.0 Following iOS 15.0.1 Release, Downgrading No Longer Possible

Friday October 8, 2021 12:45 pm PDT by Juli Clover

Following the release of iOS 15.0.1 on October 1, Apple has stopped signing iOS 15.0, the previously available version of iOS that saw a public release on September 20. With iOS 15.0 no longer being signed, it is not possible to downgrade to that version if you've already updated to iOS 15.0.1.

iOS 15 General Feature Blue
Apple last week stopped signing iOS 14.8 as well, which means iOS 15.0.1 is the only publicly available version of iOS at this time, and those who have upgraded to iOS 15 cannot downgrade to iOS 14.

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 15.0 marks a major version update introducing Focus Mode, Live Text, on-device Siri, iCloud+, Safari changes, and tons more, with details available in our iOS 15 roundup.

iOS 15.0.1 introduced a fix for a bug that prevented an authenticated Apple Watch from being used to unlock an iPhone 13 model when wearing a face mask. It also addressed a bug that could cause the Settings app to incorrectly display a storage full alert and it fixed a bug with audio meditations for Fitness+ subscribers.

Related Forum: iOS 15

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Top Rated Comments

i.am.apple.corporate

57 months ago

I am staying on iOS 14.8 until Apple provides more clarity on their CSAM feature rollout plans.

Score: 44 Votes (Like | Disagree)

alexiaa

57 months ago

I thought that Apple was going to be supporting iOS 14 with security updates for a period of time for users who did not move to iOS 15 right away? Is that not a thing anymore? (Users on 14.x below 14.8 now have nowhere to go except 15, if I am reading this right.)

No, users on iOS 14.5 and above can still update to iOS 14.8, because Apple introduced a new mechanism called AlternateSU (Alternate Software Update) that allows OTA updates to 14.8 but not restores in iTunes/Finder, therefore blocking downgrades while still keeping 14.x supported for users who are not ready to update. But this also means that if your phone bootloops, you have no other choice than to update to iOS 15.

On iOS 14.4.2 and below, you can only update to iOS 15 as the AlternateSU mechanism didn't exist yet (unless you use the delayed software updates feature meant for enterprise managed devices, which works in a very similar way only allowing upgrades and not downgrades: https://support.apple.com/guide/mdm/managing-software-updates-mdm02df57e2a/web)

Score: 22 Votes (Like | Disagree)

lkrupp

57 months ago

Is it safe to upgrade to 15 yet or should I keep waiting?

Wait forever if you want. You’ll get no straight answer from a tech blog. 50% will say it’s a dumpster fire and 50% will say it’s fine. You can’t believe either side. But know that no software will ever be perfect and free of bugs.

Score: 18 Votes (Like | Disagree)

zorinlynx

57 months ago

No, users on iOS 14.5 and above can still update to iOS 14.8, because Apple introduced a new mechanism called AlternateSU (Alternate Software Update) that allows OTA updates to 14.8 but not restores in iTunes/Finder, therefore blocking downgrades while still keeping 14.x supported for users who are not ready to update. But this also means that if your phone bootloops, you have no other choice than to update to iOS 15.

On iOS 14.4.2 and below, you can only update to iOS 15 as the AlternateSU mechanism didn't exist yet (unless you use the delayed software updates feature meant for enterprise managed devices, which works in a very similar way only allowing upgrades and not downgrades: https://support.apple.com/guide/mdm/managing-software-updates-mdm02df57e2a/web)

So the gist of this is that Apple will let you stay on iOS 14, will still supply security updates if you stay, but they really don't want you to. If they didn't mind people being on 14 they'd keep the last version of it signed.

This is disappointing because it means Apple's continuing support for iOS 14 will be half-arsed. They really should continue signing the last release of iOS 14 if they're still supporting it.

Score: 13 Votes (Like | Disagree)

antiprotest

57 months ago

I am staying on iOS 14.8 until Apple provides more clarity on their CSAM feature rollout plans.

My guess is that they have already made up their mind on CSAM. They will not listen to customers, or the security experts, or the inventors of this technology who called it "dangerous". The backlash is causing only a short delay. They will not cancel it. Perhaps after they've rolled out other features that are supposed to appear with iOS 15, the new macOS, rolled out some of the hardware that are supposed to come these months (MacBook etc), they will turn their attention back to this and flip the switch on CSAM. And soon they will not even update iOS 14 anymore. I don't think anything will change, except moving this to the back of the queue so the other things don't get derailed.

Score: 10 Votes (Like | Disagree)