The rights and benefits of any retired employees under the former plan and trust agreement will not be affected by the adoption of the new plan adopted in this chapter. All rights and benefits of present and future employees of the city from the effective date of adoption of said plan shall be governed by the new plan as approved and adopted in this chapter; provided, however, that the rights and benefits of the presently participating city employees as to vesting under the former city pension plan which have accrued to February 14, 1978, shall not be affected by the adoption of the new plan. (Ord. 351, 1978: Ord. 349 § 3, 1978)