Idaho Code § 50-2306

All courts within the county within which said city is situated shall take judicial notice of the corporate capacity and existence of such city, and of the fact that such city is identical with and a continuation of such city formerly organized as a city under a special charter or general incorporating act. In all other courts of the state, the corporate capacity and existence of such city may be proved by a copy of the proclamation issued by the governor declaring the same to be a city, duly authenticated and certified by the clerk of such city or the secretary of state, a copy of which proclamation shall be filed in each of said offices.