Well, s/he updated the blog in April, and the profile says s/he was last online here on July 20th.
The signature says: "I haven't quit gpSP, just put it on hiatus for a while."
As said in the official release thread, the release changelog looks a bit like something Exophase would type, especially "I don't usually do minor releases but I rewrote a ton of things in gpSP 0.9, much of it during the last few days, and although I spent a lot of time debugging a few bugs inevitably crept in." We'll have to wait for Exophase to confirm.
By the way, Exophase said this about the unofficial releases:
As many of you know, I'm not terribly impressed with the unofficial builds of gpSP that exist without my consent. I have a nice rant about it in the readme, most of you have probably heard me here already anyway so I won't repeat it. Suffice it to say, I'm pretty serious about what I'm going to be doing at this point.