mayim84, I don't know what precisely he's using at the moment, sorry! Your best bet is to email him and wait for his response (though currently it may be a long wait). I'm just Steve's little helper
Is it imperative that you need to know?
Well, Immediate Mode, while supported, is deprecated from OpenGL. For good reason, though. Shaders allow for better performance. This can really help in rendering. Since Steve used to (or still does? Author page is a little dated) work for Nvidia, I would assume he would be up to date on that.
Also, I should probably put this on feature request (though its a little far-fetched). Is there a possibility of a cross-platform Anim8or (ie. Not using Wine on Linux). I'm sure there is plenty more for him to do before that becomes a possibility, but can't hurt to ask.