By accepting a testamentary or court appointment as guardian, a guardian submits personally to the jurisdiction of the court in any proceeding relating to the guardianship that may be instituted by any interested person. Notice of any proceeding shall be delivered to the guardian, or mailed by ordinary mail to the guardian's address as listed in the court records and to the guardian's address as then known to the petitioner. Letters of guardianship must indicate whether the guardian was appointed by will or by court order.