As D.C. United was formally revealing its new crest, the team store's Twitter account changed its avatar to what you see above. If you look closely, you will see faint stripes going across the material beneath the badge. Making the assumption that this is next year's jersey, we're looking at sublimated stripes running across the jersey either only on the chest, or covering the whole front of the shirt.
Over the past few years, the primary D.C. United kit has featured a plain black shirt with red and white elements on the sleeves or down the sides.