Miss. Code Ann. § 63-7-37: Miss. Code Ann. § 63-7-37

The provisions of Sections 63-7-31 through 63-7-35 , relative to lighting equipment, shall take effect and be operative with respect to equipment installed in motor vehicles after April 10, 1948, and with respect to the equipment on other motor vehicles, the provisions of Chapter 200, Laws of 1938, shall govern unless new equipment is installed therein, in which event such new equipment shall be governed by the provisions of said sections.