No action to revoke or suspend a license shall be taken until the licensee has been furnished a statement in writing of the charges against him, together with a notice of the time and place of the hearing. The statement of charges and notice shall be served upon the licensee at least 20 days before the date fixed for hearing, either personally or by registered or certified mail sent to his last known post-office address.
(Acts 1959, No. 100, p. 569, §29; Acts 1965, 3rd Ex. Sess., No. 25, p. 232, §1.)