I don't think this is true... Apps below iOS 13 won't be able to use the new system-defined UIColors, yes, and users below iOS 13 can't change to the dark-mode using a switch in the Control Center, yes.
But you've been able to change the "user interface style" for view controllers since iOS 12 [0]. And you've been able to add UIColors to asset catalogs that change depending on that setting since iOS 12 as well.
I'll be honest, I haven't tried this myself. But either this works or Apple's documentation is wrong.
But you've been able to change the "user interface style" for view controllers since iOS 12 [0]. And you've been able to add UIColors to asset catalogs that change depending on that setting since iOS 12 as well.
I'll be honest, I haven't tried this myself. But either this works or Apple's documentation is wrong.
[0]: https://developer.apple.com/documentation/uikit/uiuserinterf...