Utah Code § 78B-6-1314

If service of process is made upon unknown defendants by publication, the action shall proceed against the unknown persons in the same manner as against the defendants who are named and upon whom service is made by publication. Any unknown person who has or claims to have any right, title, estate, lien, or interest in the property, which is a cloud on the title and adverse to the plaintiff, who has been served as above, and anyone claiming under him, shall be concluded by any judgment in the action even though the unknown person may be under a legal disability.