Apple Ends Signing of iOS 18.6, Blocking Downgrades

Apple has set the signing of iOS 18.6. Users can no longer fall back on this version. The measure serves security, but also limits the downgrade options for problems. What does that mean for iPhone owners?

Apple blocks downgrade to iOS 18.6

Apple stopped the signing of iOS 18.6. It is no longer possible to return to the origin after an update to a newer version. The step follows the publication of iOS 18.6.1 and 18.6.2, which close several security gaps. Not signed iOS versions can no longer be installed technically, since Apple checks every installation on the server side. According to the company, it should be ensured in such a way that users always receive the latest protective mechanisms and do not remain vulnerable to known attacks.

July update with error loops

iOS 18.6 was released on July 29 and, in addition to security updates, also brought performance fixes. Among other things, a problem was resolved in the photo app that slowed down the memory function. Apple also adapted the rules for alternative app marketplaces in the EU. The follow-up update was particularly critical: with iOS 18.6.2 of August 20, Apple closed a gap in the Imageio framework.

The attackers were able to provoke storage errors and insert male code via manipulated image files. According to Apple, the weak point (CVE 2025-43300) was actively used against individuals in targeted attacks.

Release Notes iOS 18.6.2 / iPados 18.6.2

• Imageio, CVE-2025-43300:
• Effect: The processing of a harmful image file can lead to damage to the memory. Apple is known that this problem may have been exploited in an extremely sophisticated attack on certain people.
• Description: A problem with the letter outside the permissible area was remedied by an improved area test.
• Available for: iPhone XS and Neuer, iPad Pro 13 inch, iPad Pro 12.9 inch 3. Generation and Neuer, iPad Pro 11 inch 1. Generation and new, iPad Air 3. Generation and Neuer, iPad 7. Generation and Neuer as well as iPad mini 5th generation and new

iOS release timeline

• 2022 September 12th iOS 16 is finally published

• 2023 September 18 iOS 17 is finally published

• 2024 September 16 iOS 18 – expected final release at around 10 a.m. Pacific Time

• 2025 September 15th iOS 19 – Prognostized final publication, based on Apple’s previous release patterns

View of iOS 26

iOS 18.6 is the last major update before the generation change, an iOS 18.7 is no longer expected. In the coming month, iOS 26 will be released for all users that are currently being tested by developers and beta testers.