Bitcode and iOS 8 compatibility

I have an existing app that will support some of the CoreSpotlight framework features in iOS 9 when it is released. I am going to keep the deployment target set to iOS 8 for some time after that.

If I compile this app in the current Xcode 7 seed with enabled bitcode and install it to iOS 8 device via internal Testflight testing, it will crash because of the missing CoreSpotlight framework. It will work on iOS 9 devices though.

I cannot weak link CoreSpotlight framework until the bitcode option is enabled in Xcode. Disabling bitcode in the project settings and weak linking solves the problem but that leaves me without bitcode.

Now, the question: is it a limitation of bitcode itself (not supporting weak linking per se) or is it a bug on the App Store side which should have recognised that a device running iOS 8 should be feeded with the binary weak linked to the framework not available in iOS 8?