New Jersey Statutes Title 54. Taxation 54 § 53-4

a. The case shall not be reopened as to the matters agreed upon or the agreement modified by any officer, employee or agent of the State of New Jersey, and;

b. In any suit, action or proceeding, such agreement, abatement, refund or credit made in accordance therewith, shall not be annulled, modified, set aside or disregarded; provided, however, a closing agreement with respect to a taxable period ending subsequent to the date of the agreement is subject to any change in, or modification of the law enacted subsequent to the date of such agreement and made applicable to such taxable period, and each closing agreement shall so state.