As far as I can tell, the good people responsible for releasing VASSAL updates are not the same people who update the website, and the website tends to get out of date.
That's exactly right. I do releases, Rodney updates the site. Rodney's been busy lately, so the site doesn't get updated so promptly these days. That will be solved soon when we move to our new site, as then I'll be able to update the site whenever a release happens.