The blue ASU was adopted for optional wear in 2008. It was issued to new soldiers starting in the fall of 2010, and must be worn army-wide after 1 October 2014. The ASU is replacing two uniforms already in use – the "army green" service uniform and the "army white" service uniform. It will be based on the current dress uniform known as the "dress blue" uniform. It has its roots in the "army blue" uniform, which dates back to the Revolutionary War, in which the Continental Army outfitted its soldiers in blue to distinguish them from the red uniform coats of the British Army. It also recalls the Civil War Union Army's blue uniforms.