Apple will begin requiring app updates submitted to the App Store after June 1, 2015 to include 64-bit support and be built with the iOS 8 SDK, as outlined in an e-mail sent out today to registered iOS Developers. As the e-mail noted, Apple had previously announced this requirement back in October for new iOS apps, scheduled to take effect February 1, 2015.
However, this note indicates that Apple will also be applying this policy to updates to existing apps. This only affects updates submitted by developers, however, and since developers are not required to submit updates, apps built with the older SDK can likely remain available on the App Store in their present form until they otherwise need to be updated.
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