Unfortunately this old topic also pre-dates the update of the Avast web site, so your link may not have been present then. As this was at the time when avast 5 had just come out of beta testing.
It used to be a much more long winded affair hXXp://wXw.avast.com/eng/avast-4-home_pro-revision-history.html, which although no longer active, redirects into the new products, but not the new release history page.
Hopefully anyone now finding this historic topic with a google search will be rewarded.
Thanks for your update.