Apple已经告知所有iOS开发者，2015年2月开始，所有更新版本的App必需要支援64 bit及包含iOS 8 SDK，然而2015年6月开始，新建立的App一律也都要支援64 bit及至少包含iOS 8 SDK，原文部分如下：
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.
如果不确定你现有的App 是否开启这选项，直接到Xcode中的Built Setting中看看是否勾选如下图的状态：
