Minn. Stat. § 559.02
In any action brought under section 559.01, the plaintiff may insert in the title thereof, in addition to the names of such persons as are known or appear of record to have some right, title, estate, interest, or lien in or on the real property in controversy, the following: "Also all other persons unknown claiming any right, title, estate, interest, or lien in the real estate described in the complaint herein." Service of the summons may be had upon all such unknown persons defendant by publication in the same manner as against nonresident defendants, upon the filing of an affidavit of the plaintiff, the plaintiff's agent or attorney, stating the existence of a cause of action under section 559.01, and if in addition to the above known or unknown defendants, the heirs of a deceased person are proper parties defendant, and their names are unknown, and such affidavit shall further state that the heirs of such deceased person are proper parties to such action, and that their names and residences cannot with reasonable diligence be ascertained, then service of summons may be made on such unknown heirs by publication thereof in the same manner as against nonresidents, and in such case the plaintiff may insert in the title thereof the following: "Also the unknown heirs of (naming the deceased) and all other persons unknown claiming any right, title, estate, interest, or lien in the real estate described in the complaint herein." The plaintiff shall, before the commencement of such publication, file with the county recorder a notice of the pendency of the action. All such unknown persons so served shall have the same rights to appear and defend before and after judgment as would named defendants upon whom service is made by publication, and any order or judgment in the action shall be binding upon them, whether they be of age or minors; but, if they be minors when judgment is rendered, they may be allowed to defend at any time within two years after becoming of age.
Minn. Stat. § 559.02
(9557) RL s 4425; 1919 c 344 s 1; 1923 c 434 s 1; 1967 c 28 s 1; 1976 c 181 s 2; 1986 c 444