[scarface74]

Apple doesn't "force" developers to discontinue support for older OS's. Apple does require that you at least have a build that supports both 32 and 64 bit versions.

You can target at least back to iOS 7 (https://forums.developer.apple.com/thread/50410) that gives you support for phones back to the 2010 iPhone 4.

Apple also will allow you to download an older version of an app if the newest version doesn't support your hardware. I can confirm that this works back to devices that only support iOS 5 - like my first generation iPad from 2010.