Apple is now asking iOS developers to start submitting 64-bit apps to the App Store. At the moment the only 64-bit iOS device is the iPhone 5s, launching on Friday, which runs iOS 7 on a new A7 processor. The company warns
that developers wanting to support iOS 6 must continue to write in 32-bit until next month, when changes will allow hybrid 32/64-bit binaries.
The obstacle may prevent many apps from making the leap to 64-bit as soon as possible. Adoption should increase not only after the debut of hybrid binaries, but the launch of a fifth-generation iPad, which will presumably use some variant of the A7. Any other new iOS products, like a second-gen iPad mini, will likely retain 32-bit chips.