The provisions then in force continue to govern the application of penal provisions to conduct engaged in before this Act (or, for the provisions set forth in Article 1, items (iii) and (iv) of the Supplementary Provisions, those provisions; the same applies hereinafter in this Article and the following Article) comes into effect and to conduct engaged in after this Act comes into effect in the cases in which prior laws are to continue to govern pursuant to the provisions of these Supplementary Provisions.