All annual licenses shall terminate on the last day of April of each year, where no provision to the contrary is made. The City Clerk shall mail to all licensees of the city a statement of the time of expiration of any annual license three weeks prior to the date of such expiration, provided that a failure to send out such notice, or the failure of the licensee to receive it shall not excuse the licensee from a failure to obtain a new license or a renewal thereof, nor shall it be a defense in an action for operation without a license.
('72 Code, § 110.007)