It looks like that A7 processor Apple is baking into each and every iPhone 5S is about to get used a helluva lot more. The Cupertino-based giant is now allowing app developers to submit 64-bit apps for the iPhone 5S. Developers with apps that work on both iOS 6 and iOS 7 will be limited to 32-bit for the time being, but the company is set to support a single app binary for both 32- and 64-bit apps rolling into October.
You can submit 64-bit apps for iOS 7 today that take advantage of the power of iPhone 5s. Xcode can build your app with both 32-bit and 64-bit binaries included so it works across all devices running iOS 7. If you wish to continue to support iOS 6 then you will need to build for 32-bit only. Next month we will be making changes that will allow you create a single app binary that supports 32-bit on iOS 6, as well as 32-bit and 64-bit on iOS 7.