Apple has officially ceased signing iOS 17.6, which means that it is now stopping iPhone users from downgrading to this version of iOS. The move comes shortly after the release of iOS 17.6.1 on August 7, making it impossible to downgrade to iOS 17.6.
Why? This is standard practice for Apple, as the company typically stops signing older iOS versions within a few weeks of releasing a new update. The main aim is to encourage users to maintain their devices on the latest software, which often includes critical security patches. Therefore, if you were planning to downgrade to iOS 17.6, it’s no longer an option.
While iOS 17.6 brought up some general bug fixes and security enhancements, iOS 17.6.1 addressed a big issue that could hinder the enabling or disabling of Advanced Data Protection, which is why iOS 17.6.1 was released in the first place. Therefore, it’s strongly recommended that users upgrade to iOS 17.6.1 instead of attempting to downgrade to iOS 17.6. We have an entire series of tutorials if you’re facing any issues with iOS 17.6.1.
With the termination of iOS 17.6 signing, iPhone users are now locked into running iOS 17.6.1 or later versions on their devices.
More here.