Earlier this year, Apple announced that new apps submitted from Feb. 1, 2015 on must offer 64-bit support and be built with the iOS 8 SDK.
And in an email sent to registered developers today, Apple said those same requirements will apply to any app updates submitted starting on June 1, 2015.
Heres the complete email:
As we announced in October, 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. Beginning June 1, 2015 app updates will also need to follow the same requirements. 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.
If you have any questions, visit the Apple Developer Forums.
Best regards, Apple Developer Technical Support
Apples first device with a 64-bit chip, the iPhone 5s, was introduced last year. Now with the exception of some lower-end devices, like the original iPad mini and the iPhone 5c, most all of Apples iOS products now support the technology.