On a recent attempt to submit an app I built with 2014.2468 using OSX 10.8.5 (XCODE 5.1.1), my client pointed out that the submittal received a warning from Apple:
WARNING ITMS-9000 "Missing 64-bit support. Starting February 1, 2015, new iOS apps uploaded to the App Store must include 64-bit support and be built with the iOS 8 SDK, included in Xcode 6 or later. To enable 64-bit in your project, we recommend using the default Xcode build setting of "Standard architectures" to bulid a single binary with both 32-bit and 64-bit code."
It seems like this would be no problem for the time being, but is there anything I can do now to build the binary with both 32 and 64 bit code?