Apple has stopped signing iOS 15.3 for the iPhone. This means that anyone who wants to install iOS must install iOS 15.3.1 on their device.
Apple is known to stop signing older versions of iOS to make sure that users are running the latest version of Apple’s software for the iPhone.
Newer versions of each software not only include new features and bug fixes but performance improvements and security updates as well.
Now, anyone who attempts to restore an iPhone will have only iOS 15.3.1 as an option.
Those who are on the developer and public beta train can, of course, still install the iOS 15.3 beta.
While some do enjoy the option of downgrading to an earlier version of iOS as a backstop to issues with a newer version of the software, that opening is usually short.
If you are running iOS 15.3.1 and experiencing issues, you’ll need to wait until Apple releases a newer update.
iOS 15.3.1 is the latest public version of iOS 15 and coming with it the usual mix of enhancements and bug fixes.