Changes to Payment Dates Require Corrective Invoices in KSeF

Summary

Both an incorrect payment date included on an original invoice and a payment date changed later by agreement with the customer should be documented through a corrective invoice in Poland’s National e-Invoice System, or KSeF, where the original document was a structured invoice.
The payment date is not a mandatory VAT-invoice element, but it can be commercially material. A correction is required where leaving the original information unchanged would cause the invoice to misrepresent the parties’ agreement or potentially mislead the customer about when payment becomes due.
The correction is formal and does not change the taxable amount, output VAT or gross invoice value. Businesses should nevertheless connect contract amendments and credit-control decisions with their KSeF processes so that payment-term changes generate an appropriate corrective document and audit trail.

Article

A Polish individual tax ruling has clarified the invoicing consequences of changing the payment date shown on a structured invoice.

The analysis covers two situations. In the first, the payment date was wrong when the invoice was issued, for example because the invoice stated 14 days although the parties had agreed on 30 days. In the second, the invoice correctly reflected the original agreement, but the parties subsequently extended the deadline through an amendment, email exchange or other commercial agreement.

Article 106j(1)(5) of the Polish VAT Act requires a corrective invoice where an error is identified in an invoice item. According to the published analysis, the concept of an invoice item is not limited to information that Article 106e identifies as mandatory. It can also cover optional information voluntarily included by the supplier, particularly where that information is material to the commercial relationship. [prawo.pl]

The payment date is commercially significant because it determines when the receivable becomes due and may affect interest, collection processes and enforcement. Accordingly, an incorrect payment date should be corrected. A subsequent agreed change should also be reflected so that the invoice remains aligned with the parties’ current arrangement.

Where the original document was issued as a KSeF structured invoice, the corrective invoice should generally also be issued through KSeF. It should identify the original KSeF invoice, show the correct payment date and may explain whether the correction results from an original error or a later agreement.

The correction does not affect the VAT base, output tax or gross consideration. It should therefore be distinguished from value corrections that affect the tax period or require adjustments by the customer. Nevertheless, it remains an important compliance document.

The position comes from an individual ruling issued by the Director of National Tax Information on 10 July 2026, reference 0114-KDIP1-1.4012.365.2026.1.MM. [prawo.pl]

Businesses should incorporate a KSeF step into payment-term amendment procedures. Treasury, credit-control and sales teams should not amend contractual due dates without notifying the invoicing function. Systems should also distinguish a changed payment date from amendments to price, discounts or consideration, which may have different VAT-reporting consequences.

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