Tennessee Code Title 9. Public Finances § 9-21-908

Unless the outstanding obligations are retired at the time of delivery of the general obligation refunding bonds, then the general obligation refunding bonds shall not be issued to refund the outstanding obligations unless the outstanding obligations shall mature by their terms, or shall be subject to redemption and be called for redemption within ten (10) years from the date of delivery of the general obligation refunding bonds. However, this time limitation shall not apply if the comptroller of the treasury or the comptroller's designee approves a greater period in the comptroller of the treasury's or the comptroller's designee's report on the proposed refunding plan.