I sure hope not. The official site has links to 3 mirrors, one of which doesn't work (curse), one was last updated in 2009 (wowinterface), and the third wasn't far behind that in Feb 2010 (Google Code). I use the spartanui beta downloaded from Google Code with no issues other than having to keep bartender and ouf updated, and I'd probably fix it if patch 4.2 breaks it. But it seems like 4.2 is only going to break addons that depend on the combat log event unfiltered, so I doubt it will need fixing.
Still would be nice to have newer features. Zilver was the major coder for 2.6.3beta, and has retired from addon development....as stated on the fan update page, which hosts the same version as on Google Code.
http://www.wowinterface.com/download...FanUpdate.html