Back in October Apple revealed that new app submissions from February will have to be made available in 64-bit.
Now the company has sent out an email to their developers, reminding them about the new 64-bit app rule, which comes into place on the 1st of February.
As a reminder, beginning February 1, 2015 new iOS apps submitted to the App Store must include 64-bit support and be built with the iOS 8 SDK. To enable 64-bit in your project, we recommend using the default Xcode build setting of “Standard architectures” to build a single binary with both 32-bit and 64-bit code.
As well as submitting new applications with 64-bit support, developers who are updating their existing applications will also have to add in 64-bit support in future updates.