Which software sport my iPhone 7

I have iPhone 4S iOS 9.3.6, iPhone 6 iOS 12.5.5, iPhone SE iOS 15.0.2, iPhone 8 iOS 15* and an iPad Pro iPadOS 15.0.2 and iPhone 12 Pro iOS 15.0.2. Prior to that, I had iPhone 3GS, which I have stopped using because it is carrier-locked.

I have been updating all these devices whenever a new iOS are released. I have never encountered any issue whatsoever after any update

*Just an exception.