That's according to Blizzard themselves. It is REALLY weird that this is hitting GOG when you can't even get it on Battle.net (so far as I'm aware). I assume that Blizzard is happy to make it available, and they have the added benefit of being able to foist all the support issues off on GOG instead of dealing with them themselves. Curiously, Hellfire is not available.
Has anyone tried this out yet? I'm curious if this has aged well at all.