Why does the ocp camouflage of the US military look old?

Because it has a strong camouflage ability. The origin of OCP name, Multicam Camouflage, means "compound camouflage", also known as "MC Camouflage". Suitable for terrain similar to desert to jungle transition (but not all terrain), it is one of the most comprehensive camouflage patterns in the world. On the basis of multi-camera camouflage, OCP camouflage is improved by the US military to make it more suitable for some terrain in Afghanistan, and its color is still different from MC camouflage.