Apple Stops Signing iOS 18.3.2

Apple today stopped signing iOS 18.3.2, a week after releasing the iOS 18.4 update. Now that iOS 18.3.2 is not being signed, iPhone users who have upgraded to iOS 18.4 are not able to downgrade to a version of iOS 18.3.

It is typical for Apple to stop signing an older version of iOS after releasing an update, and the process keeps iPhone users from installing outdated versions of iOS. "Signing" refers to a server-side verification check that's done when versions of iOS are downloaded onto an iPhone. Only software that passes the verification check is able to be installed.

Preventing downgrading ensures that customers have the latest security improvements and are not vulnerable to known attacks or security holes.

The iOS 18.4 update fixed more than 60 vulnerabilities, so it is a good idea to install the software if you have not done so already.