N.Y. Multiple Residence Law § 306

§ 306. Service of notices and orders. Every notice or order issued by\nthe department relative to a premises shall be served at least thirty\ndays before the time for compliance therewith. It shall be sufficient\nservice of a departmental notice or order, if it is posted in a\nconspicuous place upon the premises affected and a copy thereof mailed,\non the same day it is posted, to the person to whom it is directed at\nthe address filed by him in the department, and, if his address is not\nso filed in the department, then in such case, such notice shall be sent\nby registered mail to his last known address or place of residence.\n