Wis. Stat. § 992.04

Any bonds authorized prior to June 22, 1923, to be issued in accordance with the procedure provided by ch. 67 by any municipality defined in ch. 67 for the purpose of refunding bonds or other existing legal indebtedness of such municipality issued or outstanding previous to January 1, 1922, shall be legal, valid and binding to the same extent as if such municipality, at the time of authorizing such issue, still had the power formerly possessed by it to issue refunding bonds.