Migrate from Silverlight 2 to 3

Just a quick note on this as I still found people stuck with this error:

Error: Unhandled Error in Silverlight 2 Application
Code: 2106   
Category: InitializeError      
Message: Failed to load the application. It was built with an obsolete version of Silverlight    

This might happen every time you download a sample which was build with Silverlight 2, and you open it in VS2008 updated to Silverlight 3.

The solution is very easy:

Delete the xap file in ClientBin folder and rebuild the Silverlight project.