The amendment to the Code of Administrative Procedure, which came into force in September 2021, introduced major changes to the institution of annulment of administrative decisions. Not all of them have gained the recognition of representatives of legal theory and practice, who have drawn attention to the departure of the legislator from the real intentions of the Constitutional Court, whose ruling was the basis for the introduction of the new regulations. The biggest controversy concerns the introduction of a time limitation on the initiation of proceedings to declare an administrative decision invalid; according to the new regulations, if thirty years have elapsed from the date of service or announcement of the decision, proceedings to declare it invalid shall not be initiated. This restriction excludes the possibility of obtaining a prejudiciate indicated in the provisions of the Civil Code allowing the claiming of compensation for damages caused by defective administrative decisions. In addition, the amending law, in Article 2, para. 2, provides for the discontinuance, by operation of law, of administrative proceedings for the annulment of administrative decisions initiated after the expiration of thirty years from the date of service or announcement of such decisions, and not concluded before the date of entry into force of the amending law, by a final decision or order. This article aims to analyze the amendment and discuss the most problematic provisions identified above.