Apple Has Made It Impossible to Downgrade From iOS 26

If you installed iOS 26 on your iPhone, it is now officially impossible to downgrade. Apple has stopped "signing" iOS 18.6.2, which means you cannot install iOS 18 on your iPhone. If you're currently ...
PCMag

Make Sure You Really Want iOS 26. There's No Going Back to iOS 18

As it usually does after a new iOS release, Apple has stopped validating its older mobile OS. So, if you upgraded to iOS 26, you better get comforable with Liquid Glass.

Apple just made it impossible to downgrade from iOS 26 — what you need to know

Apple has reportedly stopped signing iOS 18.6.2, meaning users will no longer be able to downgrade back from iOS 26.