This is a release does not include any functionality changes over Prism 4.1 Desktop. These assemblies target .NET 4.5. These assemblies also were compiled against updated dependencies: Unity 3.0 and Common Service Locator (Portable Class Library).
UPDATE: The Microsoft.Practices.Prism.UnityExtensions.dll has been recompiled against Unity version 3.0.1208.
UPDATE: The Microsoft.Practices.Prism.UnityExtensions.dll has been recompiled against Unity version 3.0.1208.