I selected Check for Updates today and installed all the updates Visual Studio for Mac version 7.1.5 (build 2)
When running the project it then asked me to download version 9 of XCode for iOS 11
in my Xamarin Forms PCL solution
I have installed XCode 9
Then got this error:
There was a problem parsing the XML in this document (on the LaunchScreen.storyboard)
Silly me had downloaded XCode 9 but not opened it so it applied the update.
So I would like to report a smooth upgrade to XCode 9 and iOS 11 support