Microsoft.Fakes Error 106

I'm using Visual Studio 2013 Ulitmate and trying to "Add Fakes Assembly" to a test project. The initial build gives me this error:

Error 106 Assembly 'Core.Fakes, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' uses 'Microsoft.QualityTools.Testing.Fakes, Version=12.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' which has a higher version than referenced assembly 'Microsoft.QualityTools.Testing.Fakes, Version=11.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'