not sure on your cable modem model, but most of the new cables coming out on the market are docsis 2.0 ready, but also backwards compatible to docsis 1.1. most cable companies haven't widely deployed docsis 2.0 as there arent a lot of hardware vendors making 2.0 equipment, the equipment is expensive, and is still in trials to see how efficient it works, etc etc.
i wouldn't sweat over this much. wait a year or two and docsis 2.0 should start being implemented on your provider's network.