Wis. Stat. § 992.07
Every corporation organized under any general law for any of the purposes embraced in s. 180.0301 and existing September 1, 1898, shall continue in existence in the same manner and have the same powers as if lawfully organized under this chapter and be governed by these statutes; and every joint stock company organized under ch. 73, Revised Statutes of 1858, prior to the first day of January, 1875, shall be deemed legally organized and remain in existence and unaffected by the repeal thereof. Whenever articles of association have been filed since the enactment of the Revised Statutes of 1878, and prior to September 1, 1898, in the office of the secretary of state or the register of deeds for any of the purposes authorized by ch. 86, Revised Statutes of 1878, and an organization has been formed under said articles, such organization is hereby declared to be legal and the corporation to be duly organized.
Wis. Stat. § 992.07