error at services.AddMvc();

[petervn]

i clone your code at http://stephenwalther.com/archive/2015/01/13/asp-net-5-and-angularjs-part-2-using-the-mvc-6-web-api and run on visual Studio 2015 CTP. in file project.json if you use
"Microsoft.AspNet.Mvc": "6.0.0-beta1", as your above tutorial, it will cause error
in startup.cs at line services.AddMvc(); . I resolve this problem by use "Microsoft.AspNet.Mvc": "6.0.0-beta3", but why? can you explain it for me , and i also ask you a question : "when is MVC 6 release?"

thank you.