N.H. Rev. Stat. Ann. § 228-A:13

The provisions of this chapter shall not in any way limit, restrict, or alter the obligation or powers of the state to carry out and perform in every detail each and every promise, covenant, agreement, or contract made or entered into, prior to the enactment of this chapter, or limit, restrict, or alter the powers, rights, authority, duties, or obligations of the treasurer or the commissioner of transportation or any other officer of the state to do and perform each and every act or thing required on the part of the state or any such officer to be done or performed by any such promise, covenant, agreement, or contract.