Minn. Stat. § 284.15
The owners of such lands at the time of forfeiture, all persons in actual possession of such lands, claiming adversely to the plaintiff, and all other persons claiming any interest in or lien thereon adverse to the plaintiff, so far as shown of record or known to the attorney for the plaintiff, shall be made defendants in the action; provided, that failure to join any person as a defendant shall not impair the effect of the action as to those joined. It shall not be necessary to specify in which parcels of land the defendants, respectively, are interested. The plaintiff may also add to the names of the defendants in the summons, complaint, and other papers in the action the following: "also all other persons or parties unknown claiming any right, title, estate, lien, or interest in the real estate described in the complaint herein," and all such persons and parties shall thereupon be deemed to be joined as defendants, and, upon being served as herein provided, shall be bound and concluded by the judgment.
Minn. Stat. § 284.15
(2190-9) 1939 c 341 s 9