N.H. Rev. Stat. § 261:77
Except as provided for nonresidents, no number plates other than those procured from the department or authorized by the director shall be displayed on any vehicle so operated. No expired number plates shall be displayed. This prohibition on the display of expired number plates shall not supersede the provisions of RSA 261:89-a, nor shall it apply in those cases in which expired number plates are displayed in conjunction with current and authorized plates issued by the director which contain the designation "antique". During the month of expiration, the owner of a duly registered vehicle which has been properly registered for the succeeding year may display the number plates for that year in place of those of the current year. The provisions of this section shall also apply to a vehicle which has been exchanged for a vehicle properly registered.
RSA 261:77
1911, 133:5. 1921, 119:5. PL 103 :2. 1927, 76:1. 1937, 113:7. 1939, 140:1. RL 119:2. RSA 263:3. 1981, 146:1. 1994, 384:2, eff. June 9, 1994.