S.C. Code Ann. § 48-5-130: Subsequent amendments not to affect prior agreements or vested rights.

Subsequent amendments to this chapter may not limit the rights vested in the authority with respect to agreements made with, or remedies available to, the holders of bonds issued under this chapter before the enactment of the amendments until the bonds, with all premiums and interest on them, and all costs and expenses in connection with the proceeding by or on behalf of the holders, are fully met and discharged.