New York Consolidated Laws, Real Property Actions and Proceedings Law - RPA § 1311. Necessary defendants

1. Every person having an estate or interest in possession, or otherwise, in the property as tenant in fee, for life, by the curtesy, or for years, and every person entitled to the reversion, remainder, or inheritance of the real property, or of any interest therein or undivided share thereof, after the determination of a particular estate therein.

2. Every person having a right of dower or an inchoate right of dower in the real property or any part or share thereof.

3. Every person having any lien or incumbrance upon the real property which is claimed to be subject and subordinate to the lien of the plaintiff.

4. Where the mortgage is upon any of the public utilities regulated by the public service law, the public service commission.