At the moment, the current server source and login server source on the SVN (
http://code.google.com/p/projecteqemu/source/list) are 'compatible' with the current live EQ client (which obviously includes the Underfoot expansion).
I put 'compatible' in quotes, as there are no doubt some features that don't work (that work in the 'supported clients, Titanium, SoF & SoD) as it is not our intention to have the live client fully playable, but just to keep relatively up to date with the current client so that it should be relatively easy to support, for example the Underfoot download from Steam, or any future expansions, if so desired.