UPO (KSeF acknowledgment)

The UPO is the official proof, issued by KSeF, that an invoice has been accepted by the Polish system.

Definition

The UPO, short for Urzędowe Poświadczenie Odbioru ("official acknowledgment of receipt"), is the confirmation issued by Poland's KSeF (Krajowy System e-Faktur) when an electronic invoice has been submitted and accepted by the platform.

It embodies the authority's confirmation that the invoice has successfully passed the national system's checks.

Role

The UPO serves as enforceable proof of acceptance:

• it certifies the date and time at which KSeF took charge of the invoice;
• it accompanies the assignment of the Numer KSeF, the invoice's unique identifier;
• it can be retained as supporting evidence in the issuer's audit trail.

Good to know

Until a UPO is issued, the invoice is not deemed properly received by the system: the UPO is therefore an essential milestone in a clearance invoice's lifecycle. A rejected submission produces no UPO but an error message, which must be fixed before resubmitting.

The UPO takes the form of a structured electronic document that the issuer keeps.