Hello, I have xCode 10.1 on my Mac. I downloaded an older xcode project, which was written in Swift 2, it won't open in xcode 10.1. So I downloaded xcode 8.3.xip to try to convert it to Swift 3. But the xcode 8.3 won't open. Does xcode 8.3 co-exist with xcode 10.1? Does xcode 8.3 run on Majove at all? What can I do? Thanks.