I phone software update

If you're on iOS 15.7 or earlier and can't update your phone to iOS 16, you need to have an iPhone 8 or newer or an iPhone SE 2020 or later. If you have one of those phone types and/or are already on iOS 16, your iPhone may have trouble recognizing the update. Try rebooting your phone. If that doesn't work, check your network settings and make sure you have a good connection.

What happens when you attempt to update?

Any error messages?

What is the existing version of iOS?