Iowa Code Title XV. Judicial Branch and Judicial Procedures [Chs. 595-686] § 633.312. Joinder of parties

In all actions to contest or set aside a will, all known interested parties who have not joined with the contestants as plaintiffs in the action, shall be joined with proponents as defendants. When additional interested parties become known, the court shall order them brought in as party defendants. All such defendants shall be brought in by serving them with notice pursuant to the rules of civil procedure.