How do I update my iPhone 7 Plus to iOS 17?

You can update an iPhone 7 Plus to the latest release of iOS 15 – currently iOS 15.8.3.

You cannot update an iPhone 7 Plus to iOS 17 – or to iOS 16, for that matter. iOS 15 is the end of the line. If you want iOS 18, you will need to purchase a new iPhone.

iOS 17 is no longer available. Even it it was, the iPhone 7 could not run it.

To update to iOS 18, you will need an iPhone XR or higher model.

You can't. The 7 can't go later than iOS 15.8.x

You don’t.