I just upgraded to Xcode 10. It has built-in bitbucket support. I am already using bitbucket. Always do "add existing remote" after create a repository on the website. So no problem so far. With Xcode 10, after I added my bitbucket account in Xcode preference, I tried "create (my app name) remote ..." for a test project. But I got "An unknown error occurred". Tried both HTTPS and SSH, still not working.