Just purchased a bottle of 2007 Double Bastard a couple of weeks ago. We are hanging on to it until we get another bottle of 2009 DB so we can taste them side-by-side. I am not sure if the recipe has changed much (if at all).
We did have the Stone 11th Anniversary the other night, and it was a completely different beer. Any hop flavor it originally had, had completely disappeared with age. What was left was a heavy chocolate (slightly smokey) flavor.