Unless otherwise provided for in these Supplementary Provisions, the provisions of the Income Tax Act as amended by Article 1 (hereinafter referred to as "the new Income Tax Act" in the provisions up to Article 12 of the Supplementary Provisions) apply to income tax for tax year 2020 and subsequent tax years, and the provisions then in force continue to govern income tax for tax year 2019 (meaning the tax year covering the period from January 1, 2019 to December 31, 2019; the same applies hereinafter) and earlier tax years.