https://arstechnica.com/gadgets/2022/06/ios-16-requires-an-iphone-8-drops-support-for-two-generations-of-older-phones/

One of the selling points of iPhones and iPads is that you'll get several years of prompt software updates, released at the same time to all devices regardless of your specific model or cellular carrier. Today Apple announced iOS and iPadOS 16, and with those new versions comes a new set of minimum hardware requirements.

Apple hasn't published a full list of compatible models yet, but its press release says that the OS will support "iPhone 8 and later." That suggests that the new update won't be compatible with phones running Apple A9 or A10 chips, including the iPhone 6S, 6S Plus, 7, 7 Plus, the first-gen iPhone SE, and the seventh-generation iPod Touch.