Iowa Code § 542B.18

Certificates of licensure shall expire in multiyear intervals as determined by the board. It shall be the duty of the secretary of the board to notify every person licensed under this chapter, of the date of expiration of the certificate and the amount of the fee that shall be required for its renewal; such notice shall be mailed at least one month in advance of the date of the expiration of the certificate. Renewal may be effected by the payment of a fee the amount of which shall be determined by the board. The failure on the part of any licensee to renew a certificate in the month of expiration as required above shall not deprive a person of the right of renewal. A person who fails to renew a certificate by the expiration date shall be allowed to do so within thirty days following its expiration, but the board may assess a reasonable penalty. For the duration of any war in which the United States is engaged the board may, in its discretion, defer the collection of renewal fees without penalty, which have or may become due from licensed professional engineers who are employed in the war effort, and residing outside the state, or who are members of the armed forces of the United States, and may renew the engineering certificates of licensed professional engineers.

96 Acts, ch 1055, §5, 6, 8