N.H. Rev. Stat. Ann. § 100-A:34-a

All retired employee and teacher members of predecessor systems of the New Hampshire retirement system except teachers retired prior to July 1, 1957, irrespective of date of retirement, shall receive benefits according to the provisions of this chapter for group I members of the New Hampshire retirement system, as provided in 1988, 193:7, effective July 1, 1988.