The Web API services app is using the latest Web API binaries. If you are using Visual Studio 2012, you can create a Web API application and upgrade to Web API preview version using the –pre parameter in the Package Manager Console. If you are using Visual Studio 2013 Preview, you are already setup with the latest preview binaries for Web API 2.0.
Once the project is setup, we use the following command to install the latest version of Entity Framework (which is version 6 beta at the time of writing).
Via William delmas