Apple Stops Signing iOS 18.6, Downgrading No Longer an Option - MacRumors
Skip to Content

Apple Stops Signing iOS 18.6, Downgrading No Longer an Option

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.

iOS 18
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.

Popular Stories

Apple TV Sans Remote Feature

New Apple TV 4K Leaked

Friday September 25, 2026 8:16 am PDT by
MacRumors contributor Aaron Perris has uncovered an image file from Apple for an unreleased Apple TV 4K, suggesting that a new model will finally be released soon. The image is specifically for an "Apple TV 4K (4th generation)" model. Apple TV 4K (4th generation) image (on a gradient) The image reveals that the Apple TV will have the same external design as the current model, with all of its...
m5 pro macbook pro launch day

Amazon Just Knocked $900 Off Apple's Latest 16-Inch MacBook Pro

Sunday September 27, 2026 8:30 am PDT by
Amazon has introduced a major discount on the 16-inch MacBook Pro with the M5 Max chip, 32-Core GPU, 36GB RAM, and 2TB SSD, now available for $3,499.00, down from $4,399.00. This is a massive $900 markdown on the high-end MacBook Pro, and it's joining a few other MacBook Pro discounts on Amazon this week. Note: MacRumors is an affiliate partner with Amazon. When you click a link and make a...
iPhone Duo Open

iPhone Duo Reportedly Facing Production Problems Ahead of Launch

Tuesday September 29, 2026 6:16 am PDT by
The iPhone Duo is reportedly facing production difficulties ahead of its October launch, with early output expected to be limited. A person said to be close to Foxconn's supply chain told China's Jiemian News that final assembly yields for Apple's first foldable iPhone were only slightly above 60% as of September 17. The source said that, under Apple's current quality standards, it could...

Top Rated Comments

winxmac Avatar
15 months ago
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.
Score: 2 Votes (Like | Disagree)
xaanaax Avatar
14 months ago
Does anyone care?
Score: 1 Votes (Like | Disagree)
15 months ago
Can we stop with this "news"? Leave it to junk websites like 925. Nobody cares about downgrading, it's not something people do regularly.
Score: 1 Votes (Like | Disagree)
ClaraStahlbaum Avatar
15 months ago
Unpopular opinion but I personally support the fact they are doing this.
Score: 1 Votes (Like | Disagree)
glsillygili Avatar
15 months ago

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?
Score: 1 Votes (Like | Disagree)
Populus Avatar
15 months ago
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…
Score: 1 Votes (Like | Disagree)
Latest Stories
Apple Pay Now Available in India With Axis Bank Cards
Apple Pay Now Available in India With Axis Bank Cards
6 hours ago
OpenAI Launches Always-On 'Dots' Agents to Rival Meta's Muse
OpenAI Launches Always-On 'Dots' Agents to Rival Meta's Muse
7 hours ago
AirPods 5 Teardown: Batteries Removable, Case Still Tough
AirPods 5 Teardown: Batteries Removable, Case Still Tough
8 hours ago
iPhone 18 Pro Owners Complain of Speaker Crackling or Popping
iPhone 18 Pro Owners Complain of Speaker Crackling or Popping
9 hours ago
You Can 'Get Ready' for iPhone Duo Pre-Orders on October 12
You Can 'Get Ready' for iPhone Duo Pre-Orders on October 12
10 hours ago
Apple Pay Reportedly Launching in India Today
Apple Pay Reportedly Launching in India Today
10 hours ago
Apple Releases New AirPods Beta Firmware
Apple Releases New AirPods Beta Firmware
11 hours ago
Apple Shares New Guide for Using iOS 27 Parental Controls
Apple Shares New Guide for Using iOS 27 Parental Controls
11 hours ago
Apple Creator Studio and Final Cut Camera Get New Features
Apple Creator Studio and Final Cut Camera Get New Features
12 hours ago
Apple Explains Why It Removed ICE Tracking Apps Last Year
Apple Explains Why It Removed ICE Tracking Apps Last Year
12 hours ago
Amazon Expands $779.99 Apple Watch Ultra 4 Deal to More Models
Amazon Expands $779.99 Apple Watch Ultra 4 Deal to More Models
13 hours ago
Switch Siri AI for ChatGPT on Your Mac
Switch Siri AI for ChatGPT on Your Mac
13 hours ago
Apple Says Emergency SOS via Satellite Now Available in Norway
Apple Says Emergency SOS via Satellite Now Available in Norway
13 hours ago
AppleCare Guide: Is it Worth Paying For?
AppleCare Guide: Is it Worth Paying For?
13 hours ago
Apple Reportedly Planned to Replace 5,000 Support Employees With AI
Apple Reportedly Planned to Replace 5,000 Support Employees With AI
14 hours ago
Apple Planning to Launch Products Faster and More Often
Apple Planning to Launch Products Faster and More Often
14 hours ago
Amazon Discounting New Mac Mini and Mac Studio Alongside Early Prime Day Deals on Monitors
Amazon Discounting New Mac Mini and Mac Studio Alongside Early Prime Day Deals on Monitors
15 hours ago
New Apple TV 4K Hinted at in Support Document
New Apple TV 4K Hinted at in Support Document
16 hours ago
iPhone Duo Reportedly Facing Production Problems Ahead of Launch
iPhone Duo Reportedly Facing Production Problems Ahead of Launch
17 hours ago
Here's Why iPhone Apps Were Crashing
Here's Why iPhone Apps Were Crashing
17 hours ago
iPhone Duo Gets a Virtual Walkman App Ahead of Launch
iPhone Duo Gets a Virtual Walkman App Ahead of Launch
19 hours ago
iPhone Duo StandBy Leak Reveals Five Unannounced Faces
iPhone Duo StandBy Leak Reveals Five Unannounced Faces
1 day ago
Apple Releases watchOS 27.0.1 for Additional Models
Apple Releases watchOS 27.0.1 for Additional Models
1 day ago
iPhone 18 Pro First Impressions: What Do You Think So Far?
iPhone 18 Pro First Impressions: What Do You Think So Far?
1 day ago
iOS 26.7.1 Fixes Vulnerability Used in Targeted Attacks
iOS 26.7.1 Fixes Vulnerability Used in Targeted Attacks
1 day ago
Early Prime Day Deals Offer Up to 65% Off Anker and Jackery Power Stations
Early Prime Day Deals Offer Up to 65% Off Anker and Jackery Power Stations
2 days ago
Apple Releases macOS Golden Gate 27.0.1 With Bug Fixes
Apple Releases macOS Golden Gate 27.0.1 With Bug Fixes
2 days ago
Apple Releases iOS 27.0.1 With Face ID Bug Fix
Apple Releases iOS 27.0.1 With Face ID Bug Fix
2 days ago
Last Chance: OWC's Best Mac Accessories Are on Sale Just for MacRumors Readers
Last Chance: OWC's Best Mac Accessories Are on Sale Just for MacRumors Readers
2 days ago
12 New Things to Expect From Apple This October
12 New Things to Expect From Apple This October
2 days ago