Apple stops signing iOS 26.5.1 after critical security fix release

Apple stopped signing iOS 26.5 and iOS 26.5.1 after releasing iOS 26.5.2 with critical security fixes, including patches for AI-powered hacking risks. The move prevents downgrades to older, less secure versions, as Apple accelerates security updates to address emerging threats.

Apple is no longer signing iOS 26.5 and iOS 26.5.1, preventing downgrades to these software versions from newer releases. The move comes after a critical security fix was issued for iPhone last week. Apple regularly cuts off versions of iPhone software after newer updates become available. The company stops signing releases once updates are proven to be generally free of major issues. In the case of iOS 26.5.1, Apple released iOS 26.5.2 on June 29. Apple gave the release a full week in the wild before closing the door on iOS 26.5.1. Apple flagged iOS 26.5.2 as an important software update https://9to5mac.com/2026/06/29/ios-26-5-2-has-fixes-for-25-security-issues-on-iphone-details-here/ for security vulnerabilities. The company even moved forward with some fixes planned for iOS 26.6 to give customers the most secure software sooner. AI-powered hacking risks were cited https://9to5mac.com/2026/06/29/apple-accelerates-security-updates-in-response-to-ai-powered-hacking-risks/ as the reason. iOS 26.5.2 is the latest version of iPhone software. iOS 26.6 beta 4 arrived yesterday for developer testing alongside iOS 27 beta 3. We should see iOS 26.6 later this month as the next general release. iOS 27 should enter public beta testing this month as well. Do more with your Apple products Apple AirTag 2 | Add Find My tracking to keys, bags, bikes, more https://amzn.to/4vjNWN1 AirPods 4 | Apple’s newest wireless headphones https://amzn.to/43ndewV AirPods Pro 3 | Apple’s best wireless headphones https://amzn.to/4ut3FYp Beats USB-A to USB-C Cable | The official CarPlay cable https://amzn.to/4mpKs7K FTC: We use income earning auto affiliate links. More. https://9to5mac.com/about/ affiliate our homepage http://9to5mac.com/ for all the latest news, and follow 9to5Mac on exclusive stories https://9to5mac.com/feature/exclusive/ , reviews https://9to5mac.com/guides/review/ , how-tos https://9to5mac.com/guides/how-to/ , and subscribe to our YouTube channel https://www.youtube.com/9to5mac