问题
I have an iOS app with its Deployment Target set to iOS 6.1 version, and the Base SDK to latest iOS. I've added both the Watchkit app and WatchKit extension targets to the project, but I need to understand how will this affect a future submission to the App Store:
1) Are two executable files generated? One for the iOS app + WatchKit extension, and another for the WatchKit app? Or is all packaged in an unique executable file?
2) Will it be automatically handled the iOS version of the device that is installing the app? I mean: will the user download and install the update from the App Store, and then she will be requested to only install the iOS app if her version is 8.1- and requested to install both the iOS app and the WatchKit app if she has iOS 8.2+ and a paired Apple Watch? Has Apple provided such information?
回答1:
Apple has provided a lot of information about WatchKit apps and extensions. I propose you read them first before going on with your project. For instance, you can find information about the WatchKit architecture and how WatchKit apps and extensions work together with iOS apps in the official docs.
Also, keep in mind that these things might completely change later this year.
Ad 1) Only one executable is generated, which includes all these parts. The user will download your app normally from the App Store as before.
Ad 2) Your iOS app will run on the lowest iOS target set in your project, in your case 6.1, even though the WatchKit app is included. However, the WatchKit app will only be available to users on iOS 8.2 and above - and of course they need the Apple Watch.
来源：https://stackoverflow.com/questions/29095351/watchkit-apps-extensions-and-ios-backwards-compatibility