Apps can have both 32 and 64 bit binaries in the same app. Apple is just saying you can no longer exclude 64-bit. Besides the effort to upgrade apps to 64-bit, the reason some developers have avoided it is it means dropping support for iOS 6.x. So while no current device will be left in the cold, any device that can't be updated to at least iOS 7 is going to stop getting app updates of any kind, unless something has changed recently.
10/20/14 at 7:25pm