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Apr 12, 2001
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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.jpg

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.

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

Aaron44126

macrumors newbie
Jun 18, 2008
9
33
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.)

[Edit]
Talking about this:
 

Cosmosent

macrumors 68020
Apr 20, 2016
2,139
2,430
La Jolla, CA
Can't speak to this latest minor update, but iOS 15 vs iOS 14.4 shows a 3-5% CPU Performance Improvement, but ALSO (& surprisingly) a 13-14% Performance Hit when using the HW-based HEVC Encoder.

It's UN-fortunate that some Apple-focused websites don't Perf Benchmark the updates.

Anybody can do it themselves if they have the right app OR apps.
 
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nyuszika7h

macrumors member
Sep 19, 2020
33
79
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)
 
Last edited:

Aaron44126

macrumors newbie
Jun 18, 2008
9
33
Is it safe to upgrade to 15 yet or should I keep waiting?
I upgraded my phone to the RC build (now iOS 15.0.1) and I have run into zero issues. I am waiting for the messages/iCloud photo deletion bug to be resolved before upgrading my wife or kids' devices. (Something they could legitimately run in to.) ...Which is why I was interested in ongoing iOS 14 support above.
 
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antiprotest

macrumors 68000
Apr 19, 2010
1,784
1,937
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.
 

zorinlynx

macrumors 604
May 31, 2007
7,017
12,594
Florida, USA
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.
 

antiprotest

macrumors 68000
Apr 19, 2010
1,784
1,937
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.
And I think they intend this to be temporary. They will not update iOS 14 forever. There's no way they will. I'd be surprised if they do it for a year.
 

apparatchik

macrumors 6502a
Mar 6, 2008
545
1,680
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 says it’s fine. You can’t believe either side. But know that no software will ever be perfect and free of bugs.

Truth is for professionals that use their Mac for a living, being 1 version behind works wonders, as in, when you update to the following macOS version, it's the most stable one. Alas, for iOS, I either wait until January, or until x.2. For mature platforms like iOS & macOS, there's very little point in rushing an upgrade for a couple of features, too little candy for potentially big pain, IMHO.

When Monterey was announced at wwdc this year, I finally went ahead and installed big sur on my main machine.
 

podycust

macrumors regular
Aug 29, 2017
137
199
Can't speak to this latest minor update, but iOS 15 vs iOS 14.4 shows a 3-5% CPU Performance Improvement, but ALSO (& surprisingly) a 13-14% Performance Hit when using the HW-based HEVC Encoder.

It's UN-fortunate that some Apple-focused websites don't Perf Benchmark the updates.

Anybody can do it themselves if they have the right app OR apps.
Why would they waste time doing that benchmarks aren’t a great one of shawing real world performance and can gamed. Raw performance isn’t everything
 

zorinlynx

macrumors 604
May 31, 2007
7,017
12,594
Florida, USA
Can't speak to this latest minor update, but iOS 15 vs iOS 14.4 shows a 3-5% CPU Performance Improvement, but ALSO (& surprisingly) a 13-14% Performance Hit when using the HW-based HEVC Encoder.

It's UN-fortunate that some Apple-focused websites don't Perf Benchmark the updates.

Anybody can do it themselves if they have the right app OR apps.
A performance hit on the HEVC encoder could mean that they're increasing encoding quality. So it may not be a bad thing overall.

Hardware HEVC encoding is already much faster than realtime at 4K 60FPS, so a 13-14% performance hit to gain higher quality is a good thing, I think.
 

Boris Bronson

macrumors member
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)
Thank you for this - nice to see an informative post on here backed up with a source.
 
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