I have a second-hand iPhone 7, my wife has an iPhone 6s. Neither supports iOS 16. The iPhone 7 was discontinued in 2019. I try to keep things for as long as possible for ecological reasons, eg most of the carbon footprint lies in the manufacturing and recycling. Besides, I don’t use the phone for gaming, which might be a reason why I haven’t noticed it being particularly slow (unlike my previous phone which was a iPhone 4s and was getting significantly slower over time).

It requires iOS 16 😭