Which docbook dtd version is in use?

[Adrian Custer <acuster gnome org>]

Hey all,

Is gnome still stuck on 
  http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd
or have we moved on to 4.3 or newer?

I see this on:
 http://library.gnome.org/devel/gdp-handbook/2.20/gettingstarted.html.en
which may be out of date.

--adrian