The Chevrolet Silverado (GMT800) phased out the C/K Series as the new generation of Chevrolet trucks starting in 1999. The Silverado as a model, should not be confused with its previous use as a trim in the C/K generation. While the 1500 and 2500 pickup trucks were released in 1999, the "classic" light-duty GMT400 C/K trucks continued in production for that first year alongside the new Silverado model, and the Heavy-Duty GMT400 pickups (alongside the GMT400 SUVs) continued in production until 2000. The new GMT800 Silverado HD (Heavy Duty) were introduced in 2001. The Silverado's have been built in four generations: the 1st Generation was from 1999 to 2007, the 2nd Generation from 2007 to 2014, the 3rd Generation from 2014 to 2019, and the 4th Generation which is ongoing.