I've decided to split the my (quite complex) storyboard into smaller chunks using the new "Storyboard refactor" feature in XCode7. I've started with one tab and refactored all the controllers within that tabbed navigation controller into separate file. But the storyboard fails to compile with "Storyboard References cannot be the destinations of relationship segues prior to iOS 9.0".
Now I've read that storyboard references should be deployable to iOS8 (which is our deployment target) "Storyboard References may now be deployed to iOS 8, OS X 10.10, and watchOS 1.". This might not be true but the problem is that I'm getting the same error even when change the deployment target to iOS 9 (and do a clean build).
Ah, silly me. Figured it out. The error message actually says where the problem is - you can't use the reference for the relationship segues - like the one between navigation (or tabbar) controller and its first child. These have to be in the same storyboard.
Though the mention of iOS9 in the error message is confusing.
来源：https://stackoverflow.com/questions/32772990/refactored-storyboard-fails-to-compile-xcode7