When multiple developers are working on the same project and we have a single storyboard, we might face conflicts in the storyboard file. And the conflicts of storyboard are difficult to resolve. Xcode 7 provides a new feature of storyboard reference. With the help of storyboard reference we can create different storyboards and link them with segues. Here's how we use them :

1. Create a new storyboard and give it some name like 'MyStoryboard'
2. Place a view controller in MyStoryboard
3. Give it a storyboard ID like 'MyViewController'
4. Go to main storyboard
5. From controls tab drag and drop Storyboard Reference control into main storyboard
6. While the Storyboard Reference is selected, open Attributes Inspector and in Storyboard drop down select MyStoryboard and provide reference ID as MyViewController
7. Connect this storyboard reference via segue with any view controller

Now with the use of Storyboard Reference different developers can work on different storyboards and easily connect them. But this feature is only available on Xcode 7 and later.