Re: Old iPhones ?
> So developers can not produce apps for the old iphones or ipads
> (iphone 5 and earlier can not run ios 11)
Not true. The app specifies its minimum and maximum(*) supported iOS versions. The minimum can certainly go back to iOS 8, and possibly a bit earlier. All that has been announced is that the max supported version soon has to be 11.
(*) The max version is not a strict limit; if you try to install an app that e.g. doesn't support iOS 11 on an iOS 11 device it will run, but iOS will provide an iOS-10-like compatibility environment for it. This might involve, for example, pretending that the screen is a different size and scaling the content.