So I've released an app into the store and now want to prepare it for iOS8. There are things that do not work on iOS8 anymore (e.g. the way the app registers for notifications), and I've fixed them by adding in the new non-deprecated methods.
I read somewhere, however, that we should not submit an app built with XCode6 beta. If this is the case, how do we ensure that we have an iOS8 compatible app in the store when iOS8 comes out?
Apple usually release a "Golden Master" build of Xcode to developers a week before the official launch of Xcode and the new iOS version. The idea is that you've done all of your development and testing using the Beta and then use the GM to submit your App. As the GM is virtually identical to the full release, any app archived and submitted using it will be fully compatible with the newly released iOS.
Apple will release the GM (Gold Master) of iOS 8 and Xcode 6 before they release it to the public. Giving you the chance to submit your iOS 8 app before iOS 8 is released.
And NO you will not be able to submit any apps build with the beta version of Xcode.
来源：https://stackoverflow.com/questions/25060030/can-we-submit-xcode6-beta-builds-how-to-prepare-app-for-ios8