Colo. Rev. Stat. § 24-51-1707
A casual employee who has been approved or has applied, and is ultimately approved, for status as an affiliate member as of December 31, 2009, shall remain an affiliate member and the benefits provided for pursuant to the DPS plan document shall govern at the time of retirement, unless such status is revoked pursuant to the DPS plan document. Any applicant for affiliate member status shall complete payments in accordance with the DPS plan document or be subject to revocation of affiliate member status. On or after January 1, 2010, further applications for affiliate membership shall not be permitted, and all eligible benefits payable to the existing affiliate members shall be based on the highest average salary, as defined in section 24-51-1702 (17), and benefit descriptions, as detailed in sections 24-51-1715, 24-51-1729, and 24-51-1734 to 24-51-1746.
C.R.S. § 24-51-1707