Section 71G. No person shall work as an elevator operator unless he has received a license therefor from the commissioner of public safety. Licenses shall be valid throughout the commonwealth but shall not be assignable or transferable. A license shall continue in force until the date of birth of the licensee occurring more than twelve months but not more than twenty-four months after the date of such license unless suspended or revoked for incompetence or untrustworthiness of the licensee. If any such license or the renewal thereof expires in an even year, any subsequent renewal shall expire on the next anniversary of the licensee's date of birth occurring in an even year. If any such license or renewal thereof expires in an odd year any subsequent renewal shall expire on the next anniversary of the licensee's date of birth occurring in an odd year. A license issued to a person born on February twenty-ninth shall for the purposes of this section expire on March first. Licenses not renewed at the expiration date shall become void, and shall after one year be reinstated only by reexamination of the licensee. A notice of the date of expiration of a license shall, at least thirty days prior to such date, be sent to the licensee. The fee for said license and for each renewal thereof shall be determined annually by the commissioner of administration under the provisions of section three B of chapter seven.