Apple Stops Signing iOS 17.5.1, Downgrading No Longer an Option

Apple today stopped signing iOS 17.5.1, preventing iPhone users from downgrading to that version of iOS. The update is no longer being signed after the July 29 release of iOS 17.6.

iOS 17
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.

This policy encourages users to keep their operating systems up to date, ensuring they have the latest security enhancements.

iOS 17.5.1 addressed a corruption bug that could cause deleted photos to reappear on an iPhone. There were no notable features in the iOS 17.6 update, with Apple adding unspecified bug fixes and security updates.

Popular Stories

iPhone 17 Pro 3 4ths Perspective Aluminum Camera Module 1

New iPhone 17 Pro Details: Brighter Display, Best Battery Life, and More

Wednesday September 3, 2025 5:33 am PDT by
Apple's iPhone 17 Pro and iPhone 17 Pro Max models will feature a number of significant display, thermal, and battery improvements, according to new late-stage rumors. According to the Weibo leaker known as "Instant Digital," the iPhone 17 Pro models will feature displays with higher brightness, making it more suitable for use in direct sunlight for prolonged periods. The iPhone 16 Pro and...
iPhone 17 Pro in Hand Feature Lowgo

iPhone 17 Pro's Biggest Design Mystery is Finally Solved

Friday September 5, 2025 9:33 am PDT by
Apple is set to unveil the iPhone 17 series in just four days from now, and the biggest design mystery surrounding the Pro models has finally been solved. In a report outlining his expectations for Apple's event next week, Bloomberg's Mark Gurman said the iPhone 17 Pro models will have "a new cutout area on the bottom two-thirds of the phone that doubles as the wireless charging area."...
iPhone 16 Battery Life Feature

iOS 26's New Battery Life Mode is Limited to These iPhone Models

Wednesday September 3, 2025 1:19 pm PDT by
iOS 26 introduces an Adaptive Power Mode on the iPhone, alongside the existing Low Power Mode. Apple says Adaptive Power Mode can make "performance adjustments" when necessary to extend an iPhone's battery life, including slightly lowering the display brightness, allowing some activities to "take longer," and automatically turning on Low Power Mode when the iPhone's remaining battery life...
iPhone 17 Pro Dark Blue and Orange

iPhone 17 and iPhone 17 Pro: Release Date and Pre-Orders

Sunday September 7, 2025 3:15 pm PDT by
Apple will be holding its annual iPhone event on Tuesday, September 9, to unveil the iPhone 17, iPhone 17 Air, iPhone 17 Pro, and iPhone 17 Pro Max. Assuming that Apple sticks to its familiar pattern, the iPhone 17 series should be available to pre-order starting Friday, September 12 at 5 a.m. Pacific Time / 8 a.m. Eastern Time. The release date for the devices should be one week later, on Fr...

Top Rated Comments

Victor Mortimer Avatar
14 months ago
The EU should really go after them for this behavior too.

You should be able to install ANY OS that the hardware can support.
Score: 1 Votes (Like | Disagree)
Populus Avatar
14 months ago
This was expected, especially for 17.5.1 which was a quick fix for 17.5. Also 17.6 packs a significant amount of security patches.
Score: 1 Votes (Like | Disagree)