Apple Stops Signing iOS 17.5.1, Downgrading No Longer an Option - MacRumorsOpen MenuShow RoundupsShow Forums menuVisit ForumsOpen Sidebar
Skip to Content

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

iOS 27 Next to iPhone

Here's When iOS 27 Rolls Out Today in Every Time Zone [Update: It's Out]

Sunday September 13, 2026 3:00 am PDT by
Update 10:04 a.m.: iOS 27 is rolling out now, though it may take a bit for all users to see it, so keep checking! Apple is about to release iOS 27, which will finally deliver more advanced Siri AI capabilities as well as a variety of other refinements, improvements, and new features to iPhones. It's Apple's biggest software update of the year, and Apple announced at Wednesday's iPhone event...
iOS 27 Icon iPhone

iOS 27 Available Now With These 8 New Features

Monday September 14, 2026 9:00 am PDT by
Update — 10 a.m. Pacific Time: Apple has released iOS 27. During its iPhone 18 Pro and iPhone Duo event last week, Apple announced that iOS 27 will be released widely on Monday, September 14. iOS 27 should be available around 10 a.m. Pacific Time / 1 p.m. Eastern Time today via the Settings app, under General → Software Update. Below, we have highlighted eight new features and...
Apple iCloud Plus expansion hero

iCloud+ Now Includes Apple TV, Apple Arcade, and Curated Apple Music Stations in Over 100 Countries

Tuesday September 15, 2026 1:43 am PDT by
Apple today announced a new subscription initiative that turns paid iCloud+ subscriptions into a broader services bundle in more than 100 countries. In select countries, Apple says every paid iCloud+ plan, including the cheapest 50GB tier, now includes Apple TV and Apple Arcade "at no additional cost," while family sharing extends the storage, TV and Arcade access to up to five people....

Top Rated Comments

Victor Mortimer Avatar
28 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
28 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)