iOS expiration
How long will iPhone 7 be supported?
iPhone 7, iOS 13
I have iPhone 4S iOS 9.3.6, iPhone 6 iOS 12.4.8, iPhone SE iOS 13.7, iPhone 8 iOS 13.7 and an iPad Pro iPadOS 13.7. Prior to that I had iPhone 3GS which I have stopped using because it is carrier (US) locked.
I have been updating all these devices whenever a new iOS is released. I have never encountered any issue whatsoever after any update because I have never downloaded anything over internet directly. Always used apps from App Store only.
Though iOS is not released for many of the above devices but I do not find any issue in its functionality.