AFAIK, the hardware architecture of our phone has been known for long, so ... as long as the binary blobs and drivers aren't incompatible with the new stuff, then the only problem is to "get all pieces together" (adapt kernel, drivers & stuff) and build the rom.
So IMHO, as long as the new versions don't require more RAM or more internal storage than our phone possesses, or requires an internal architecture far different from the one from the DHD, then our "old" DHD should devinitely run whatever upcoming version may come !