Apple Stops Signing iOS 18.6, Downgrading No Longer an Option

[MacRumors]

Apple is no longer signing iOS 18.6, making downgrades from iOS 18.6.2 or iOS 18.6.1 to iOS 18.6 impossible. iOS 18.6.1 was released a little over a week ago, swiftly followed by iOS 18.6.2 on Wednesday.

Apple often stops signing an older version of iOS, usually within a week or two after a new version is released. When an update is no longer signed, it can't be installed on an ‌iPhone‌ due to a server-side software verification check.

By no longer signing a software version, Apple ensures that customers have the latest security improvements and are not vulnerable to known attacks.

Apple's iOS 18.6.1 update re-enables blood oxygen monitoring in the United States for the Apple Watch Series 9, Apple Watch Series 10, and Apple Watch Ultra 2 running watchOS 11.6.1, which was released concurrently. That was quickly followed by iOS 18.6.2, providing important security fixes.

Article Link: Apple Stops Signing iOS 18.6, Downgrading No Longer an Option

 

[winxmac]

iOS 18.6 - 29th July 2025
iOS 18.6.1 - 14th August 2025
iOS 18.6.2 - 20th August 2025

Just about 3 weeks to go before iOS 18.7 which is my next update. I'm happy with iOS 18.6 although not entirely because of the redesigned Photos app.

 

[Populus]

I guess I’ll have to hurry up installing 18.6.1 on all my devices before Apple stops signing it, as it is a version that offers really good battery life and performance.

 

[FatLouie]

I am waiting for 18.7 to see if there are any reports for its use on a 15 Plus. I am relatively certain my iPad and iPhone will never go to 26. I don't think my Studio will go past Sequoia. For now, anyway.

 

[JosephAW]

Three updates in three weeks, wow

 

[Populus]

Okay, I seemed quite sure to stay in iOS 18.6.1, because the performance and battery life were very good, right?

However, it’s wise to have second thoughts, and I’ve been doing my research on the vulnerability patched in 18.6.2: CVE-2025-43300. It seems serious and juicy enough to consider patching it if the battery loss is not too big.

From what I’ve read, now that the patch is out there, comparing it to the previous update bad actors (at least those that still didn’t know the issue) could reverse engineer the patch to discover the vulnerability and build stronger attacks into all sorts of image files that then will be parsed by ImageIO.

Also, the fact that it’s being patched in iOS 17.7.10 indicates that the vulnerability probably wasn’t introduced with iOS 18 or a later update, but rather it has been there dormant since who knows when. IIRC the image parser ImageIO dates the Tiger days, so…

Don’t get me wrong. I’m really pissed off because it is known that this newest version is giving some sporadic problems and the battery life is lower. Let’s cross our fingers for it to not make the devices overheat. But I think the vulnerability is, this time, important enough for Apple to issue a second update to 18.6, to release it quite urgently (a patch for only one vulnerability), that it might be worth the trade off of a worse battery life.

Damn, I wish Apple’s security patches didn’t affect performance and efficiency of the devices…

 

[glsillygili]

Okay, I seemed quite sure to stay in iOS 18.6.1, because the performance and battery life were very good, right?

However, it’s wise to have second thoughts, and I’ve been doing my research on the vulnerability patched in 18.6.2: CVE-2025-43300. It seems serious and juicy enough to consider patching it if the battery loss is not too big.

From what I’ve read, now that the patch is out there, comparing it to the previous update bad actors (at least those that still didn’t know the issue) could reverse engineer the patch to discover the vulnerability and build stronger attacks into all sorts of image files that then will be parsed by ImageIO.

Also, the fact that it’s being patched in iOS 17.7.10 indicates that the vulnerability probably wasn’t introduced with iOS 18 or a later update, but rather it has been there dormant since who knows when. IIRC the image parser ImageIO dates the Tiger days, so…

Don’t get me wrong. I’m really pissed off because it is known that this newest version is giving some sporadic problems and the battery life is lower. Let’s cross our fingers for it to not make the devices overheat. But I think the vulnerability is, this time, important enough for Apple to issue a second update to 18.6, to release it quite urgently (a patch for only one vulnerability), that it might be worth the trade off of a worse battery life.

Damn, I wish Apple’s security patches didn’t affect performance and efficiency of the devices…

I don't think there is any battery life change in a minor update?