Thunderbolt 2 seems like the kind of thing that could be enabled with a firmware update. There's no overall increase in bandwidth; they just reallocate it so that instead of 2 x 10Gbps channels in each direction, you have 1 x 20Gbps channel in each direction.
I believe Thunderbolt 2 requires Intel's new Falcon Ridge controller, which won't ship until later in the year.