The latest version is the v0.97d Preview updated September 21, 2008. It takes a LONG time to program something like this, especially since it's one man writing the program on his free time (he does have a job on the side!) So no, it hasn't been updated in a while, but you have to trust Steve that he's doing the fastest and best work he can. Actually, the Preview updates mean the program is being updated faster than it normally would be! Normally it would take longer as he'd wait to fully implement features like the ART raytracer, but instead he decided to release smaller previews that included updates quicker so we could experiment with features more often and get more updates.
So honestly, it's being updated faster now than it was before.
