Colo. Rev. Stat. § 30-20-415
This part 4 shall operate to supply such legislative authority as may be necessary to validate any such securities issued prior to June 2, 1971, and other contracts of such counties executed before said date and any acts and proceedings taken before said date appertaining to the issuance of such securities or execution of other contracts by such counties or otherwise which the general assembly could have supplied or provided for in the law under which such securities were issued or such other contracts were executed and such acts or proceedings were taken; but this part 4 shall be limited to the validation of such securities, other contracts, acts, and proceedings to the extent to which the same can be effectuated under the state and federal constitutions. This part 4 shall not operate to validate, ratify, approve, confirm, or legalize any bond or coupon, other contract, act, proceedings, or other matter the legality of which is being contested or inquired into in any legal proceeding now pending and undetermined, and it shall not operate to confirm, validate, or legalize any bond or coupon, other contract, act, proceedings, or other matter which was determined in any legal proceeding prior to June 2, 1971, to be illegal, void, or ineffective.
C.R.S. § 30-20-415