Article 190 ensures that the holiday extension rules of Article 189 apply immediately. It mandates that any procedural time limits that had not already expired before the effective date of the current Income Tax Law are to be extended according to the new holiday rules. This provides immediate legal certainty for taxpayers during the transition period between the old and new tax regimes, ensuring that no deadlines were inadvertently missed due to the change in law or the timing of official holidays around the implementation date.