At first, you should sub click on newer storyboad in navigation view.
Then you see menus and...
[Open As] -> [Source Code]
So you see the XML code of storyboad, then...
you should select all and copy it.
For next step, you should sub click on older storyboad (which you want to update)
[Open As] -> [Source Code]
You see XML code And...
You should select all code and Paste !
Now you have the same two storyboards.