Arkansas 15 in southern Arkansas has been re-designated as part of a southern extension of U.S. 63.

U.S. 63 currently runs from Missouri through northeastern Arkansas. The new designation means U.S. 63 will now run through Pine Bluff, Warren, and El Dorado before heading into Louisiana and eventually intersecting with Interstate 20.
The extension of U.S. 63 southward from West Memphis, where it currently ends, will follow Interstate 40 to Hazen, then travel down what is now Arkansas 11 to Stuttgart. From there, it will follow U.S. 79 to Altheimer, where it will head south to follow the route of what is now Arkansas 15. The road will also cross the route of proposed Interstate 69 in southern Arkansas.
The designation doesn't mean any more money for the road, but will have more prominence on maps. Signs should start going up soon.