How do i update iPhone 7
How do change my iPhone id
How do change my iPhone id
The iPhone 7 can be updated to the latest version of iOS, iOS 15.5
See this links on how to do that
Update your iPhone, iPad, or iPod touch - Apple Support
How to update to iOS 15 or iPadOS 15 - Official Apple Support
I’m thinking of buying a new iPhone
How do i update iPhone 7