Xcode is Too New

Hi, I'm unable to open my storyboard. I get the following error:
Xcode is too new. This file has been edited in a version of Xcode which is unsupported by the designer. Documents saved in Xcode 9.1 format, or older, are supported.
This has just started happening? I tried re-building my solution from scratch and got the same error. I'm using Xcode verison 9.1 (9B55) . I thought to install an earlier version but can't see how that's possible. I'm using Visual Studio Community for the Mac.
I know someone has already posted something similar and said that he found a work-a-round but I could follow his solution. I've sent him a message but haven't got a response yet. Any help would be much appreciated.
Thanks,
Brian