The provisions of Article 2, paragraph (1), item (viii)-4 of the new Income Tax Act (limited to the part concerning Nonresidents) apply to income tax for tax year 2019 and subsequent tax years or to domestic source income as prescribed in Article 212, paragraph (1) of the new Income Tax Act to be received on or after January 1, 2019, and the provisions then in force continue to govern income tax for tax year 2018 and earlier tax years or domestic source income as prescribed in Article 212, paragraph (1) of the Income Tax Act before the amendment by Article 1 (hereinafter referred to as the "former Income Tax Act" up to Article 18 of the Supplementary Provisions) to be received before that date.