105 ILCS 5/34-65
Whenever any school district described in this Article has outstanding bonds which are binding and subsisting legal obligations, and the proceeds of taxes levied for the payment of the principal of and interest on such bonds have not been collected and are not available for such payments when due, the board may issue refunding bonds for an amount sufficient to pay and discharge any of the outstanding bonds with accrued interest. The refunding bonds shall bear interest at a rate of not more than the maximum rate authorized by the Bond Authorization Act, as amended at the time of the making of the contract, if issued before January 1, 1972 and not more than the maximum rate authorized by the Bond Authorization Act, as amended at the time of the making of the contract, if issued after January 1, 1972 and shall mature within 20 years from the date thereof.
With respect to instruments for the payment of money issued under this Section either before, on, or after the effective date of Public Act 86-4 (June 6, 1989), it is and always has been the intention of the General Assembly (i) that the Omnibus Bond Acts are and always have been supplementary grants of power to issue instruments in accordance with the Omnibus Bond Acts, regardless of any provision of this Act that may appear to be or to have been more restrictive than those Acts, (ii) that the provisions of this Section are not a limitation on the supplementary authority granted by the Omnibus Bond Acts, and (iii) that instruments issued under this Section within the supplementary authority granted by the Omnibus Bond Acts are not invalid because of any provision of this Act that may appear to be or to have been more restrictive than those Acts.
105 ILCS 5/34-65