Article 71 (Interim Return) of the New Act (including as applied mutatis mutandis pursuant to Article 145, paragraph (1) (Application Mutatis Mutandis to Foreign Corporations) of the New Act) applies to corporation tax pertaining to a return under the provisions of that Article whose due date for filing falls on or after the Effective Date, and the provisions then in force continue to govern corporation tax pertaining to a return under the provisions of Article 71 (Interim Return) of the Former Act (including as applied mutatis mutandis pursuant to Article 145, paragraph (1) (Application Mutatis Mutandis to Foreign Corporations) of the Former Act) whose due date for filing fell before that date.