Is it possible to backport mediawiki 1.5 ? 1.4.10 happens to be the current version and I know that 1.5.x introduces many bug and security fixes.
I don't know if it has any new libararies that impact negatively or changes to compilers/interpreters.
http://meta.wikimedia.org/wiki/Help:Running_MediaWiki_on_Ubuntu_GNU/Linux gives some information if I wanted to install it manually. But, I thought it might be a good (and not too difficult) candidate for a backport.
-Jamesc