This is what the NYS DMV has to say.
A driver with a Class D license can now operate a passenger vehicle, a limited use automobile, or:
A truck with a gross vehicle weight rating (GVWR) of 26,000 lbs. or less. (Before, a Class D driver could only operate a vehicle with a GVWR of 18,000 lbs. or less.),
A truck with a GVWR of 26,000 lbs. or less that tows another vehicle, and the other vehicle has a GVWR of 10,000 lbs. or less,
A truck with a GVWR of 26,000 lbs. or less that tows another vehicle that has a GVWR of more than 10,000 lbs., but the gross combined weight rating (GCWR) of the two vehicles together must be 26,000 lbs. or less.