N.H. Rev. Stat. § 677:19
Whenever an appeal to the superior court is initiated under this chapter and the court finds that the ordinance, or section thereof, upon which the board of adjustment, board of appeals, or local legislative body based its decision was invalid at the time such appeal was initiated, or that the application should have been approved but the ordinance was amended to prohibit the type of project applied for during the pendency of the appeal, notwithstanding the fact that the ordinance may have been amended to remove the invalidity subsequent to the initiation of the appeal or that the type of project applied for is no longer permitted, as the case may be, the court shall, upon request of the petitioner, issue an order approving the application, provided that the court finds the application complies with valid zoning and subdivision regulations existing at the time of the application.
RSA 677:19
1989, 381:2, eff. Aug. 4, 1989.