It says 4.0 in the module definitions list.
I have temporarily "retro'd" my code to be compatible with AjaxControlToolkit 3.0, which is what this is using. But we are running DNN 5.6/Visual Studio 2010/.NET 4.0/Windows-64bit. I have been trying to keep everything as new and tied into the 4.0 framework as possible.
Thanks,
jasen