How to target iOS devices lower than a specific OS using @available [closed]

Question

I have a function that is aimed at iOS 11+ marked with the following:

@available(iOS 11.0, *)

Now I need to target a different function for iOS versions less than iOS 11. How do I write that?

Answer 1

if #available(iOS 11.0, *) {} else {
    // do something (pre iOS 11.0)
}