All annual licenses issued under this division shall expire on October 15 of the year for which they are issued except as provided in section 44-24. When a valid application for license renewal has been properly filed and the existing license has not been suspended, revoked or denied by the department, the existing license shall continue in effect for not more than one hundred eighty (180) days pending formal action by the department on the renewal request. (Mont. Co. Code 1965, § 97-7; 1978 L.M.C., ch. 18, § 4.)