Wyo. Stat. Ann. § 16-5-105

No public securities may be refunded hereunder unless the holders voluntarily surrender them for exchange or payment, or unless they either mature or are callable for prior redemption under their terms within twenty-five (25) years from the date of issuance of the refunding public securities. Provision shall be made for paying the public securities being refunded within the stated period of time. No maturity of public security being refunded may be extended over twenty-five (25) years. No public security may be refunded hereunder unless the public security has been outstanding for at least one (1) year since the date of its delivery. The principal amount of the refunding public securities may not exceed the original authorized principal amount of the public securities being refunded. The principal amount of the refunding public securities may be less than or the same as the principal amount of the public securities being refunded so long as provision is duly and sufficiently made for the payment of the public securities being refunded.