Here's whatsnew per the homepage:

"For the 0.31 release all project files have been converted to SharpDevelop 3.0. They use the C# 3.0 compiler and you will need .NET 3.5 to compile. The projects still target .NET 2.0 so users with pre-WinXP can still run the emulator."

Get it here:
http://www.codeplex.com/GameKnight/Release/ProjectReleases.aspx?ReleaseId=15908

-Trebor