Iowa Code § 681.10: Report required.

At the expiration of three months from the time of first publishing notice, the assignee shall report and file with the clerk of the court a true and full list, under oath, of all such creditors of the assignor as shall have claimed to be such, with a statement of their claims, an affidavit of publication of notice, and a list of the creditors, with their places of residence, to whom notice has been sent by mail, and the date of mailing the same.