I want to update my iOS to the latest one

An iPhone 7 cannot and will not update to iOS 17. It wouldn't update to iOS 16 either. Major iOS support for your iPhone has ended and if you want the newest and greatest iOS version, then you'll need to retire your iPhone and buy a newer, more modern iPhone.

An iPhone 6s, iPhone 7, or iPhone SE 1 isn't capable of 16 or above; they require an A11 or better CPU. To install 15.7.9, use a computer or the Software Update function in Settings.

(245642)