Dotfuscator doesn't support current .NET framework?

Question

This is a Dotfuscator noob question -- I'm trying to run it on some assemblies for the first time, but I get an error saying: "Invalid assembly [foo.dll]. Input assembly [foo.dll] was compiled with a version of the .NET Framework (v4.0.30319) that is not supported by this version of Dotfuscator. Please check for an updated version of Dotfuscator."

I'm using the version that shipped with the current version of VS 2010, and I have all service packs etc installed. I have registered the product. Help > Check for updates doesn't do anything at all. I don't see any updated downloads on the Dotfuscator site.