Iowa Code § 633.487
No person, having been served with notice of the hearing upon the final report and accounting of a personal representative or having waived such notice, shall, after the entry of the final order approving the same and discharging the said personal representative, have any right to contest, in any proceeding, other than by appeal, the correctness or the legality of the inventory, the accounting, distribution, or other acts of the personal representative, or the list of heirs set forth in the final report of the personal representative, provided, however, that nothing contained in this section shall prohibit any action against the personal representative and the personal representative's surety under the provisions of section 633.186 on account of any fraud committed by the personal representative.
Iowa Code § 633.487