All laws and parts of laws relating to pension, retirement, and relief funds for any employees of the city, contained in the general or local laws of the state or in Title 11 as the same may apply and be in effect with respect to any city at the time when such city shall elect to be governed by the provisions of this part, shall continue in full force and effect, and without interruption or change as to any rights which have been acquired thereunder.
Alabama Legal Code