Contact your local Tax Assistance Centre (KIS) or check the official e-Deklaracje portal at www.podatki.gov.pl .

Introduction In the digital era of Polish tax administration, two terms are critical for compliant business operations: UPO (Urzędowe Poświadczenie Odbioru) and e-Deklaracje . While e-Deklaracje refers to the system of submitting tax and customs declarations electronically, UPO serves as legally binding proof that a submission has been successfully received by the relevant authority. Understanding both ensures legal certainty, avoids penalties, and streamlines administrative workflows.