[WCF RIA Services Version 1 Service Pack 2 is compatible with either .NET framework 4 or .NET Framework 4.5, and with either Silverlight 4 or Silverlight 5.]
Application and library templates for developing WCF RIA Services applications are made available in Visual Studio 2010 by installing the Silverlight SDK. These provide convenient starting points for developing end-to-end RIA Services applications that employ Silverlight clients. For information on installing the SDK, see Prerequisites for WCF RIA Services.
The Silverlight Application template is the most basic application template. It provides the basis for the other Silverlight Application templates available. Use the Silverlight Application template for projects that require only a single Web page and do not require any authentication, or when you just want to design everything from the ground up.
The Silverlight Navigation Application template adds features that implement the Frame and Page controls, URI mapping, Web browser integrated navigation, and browser history integration. Use the Silverlight Navigation Application template for projects that require integration and navigation between two or more web pages.
The Silverlight Business Application template builds on the Silverlight Navigation Application template, adding built in authentication services, user registration, and localization. Use the Silverlight Business Application template for projects that require these features, as well as integration and navigation between two or more web pages.
The WCF RIA Services Class Library template is an extended Silverlight Library template which is setup to work directly with RIA services. Use the WCF RIA Services Class Library template to develop reusable RIA Services code that is likely to be reused by other RIA Services enabled applications that have Silverlight clients.