Does a new payment due date require a corrective invoice in KSeF?

In an individual tax interpretation dated July 10, 2026, the Director of National Tax Information found that a corrective invoice is the proper way to correct an incorrect payment due date and document a later change to a due date shown on a KSeF invoice.

The reasoning does not support the simple claim that a correction is always mandatory. The authority also wrote that correcting optional information is not the seller's obligation, but is expected when the additional information is material to the parties.

The safest approach is to separate three situations: a date that was already wrong when the invoice was issued, a date that was correct when issued but changed later, and a date that was never shown on the invoice. An individual interpretation concerns a particular applicant and the facts described, so it is an important interpretive signal for other businesses, not universal tax advice.

The invoice already has a KSeF number, but the parties have postponed payment by 14 days. Is retaining the counterparty's email enough, or should a correction also be issued? According to the interpretation of July 10, 2026, reference 0114-KDIP1-1.4012.365.2026.1.MM, a corrective invoice is the proper method for changing a due date shown on the invoice.

This is a cautious answer, not an automatic rule for every case. A payment due date is optional invoice information, and the authority stated in the same reasoning that correcting it is not an unconditional obligation. At the same time, the authority described correction as expected when the information matters to the parties.

In practice, a business should first establish whether it is changing the content of an invoice accepted by KSeF or only contractual terms that were never recorded on the invoice. This distinction determines the next step.

What the company asked

What the Director of National Tax Information decided

Why the reasoning does not give a simple answer

The payment due date is optional information

The date on the invoice and arrangements outside the invoice

Why the stage at which the error is found matters

How to document the change in FA(3)

Does this correction change VAT?

Earlier interpretations

Who is protected by the individual interpretation

Checklist before issuing the correction

Frequently asked questions

The interpretation should be read as a whole. Its formal conclusion, reasoning and two factual scenarios support a more cautious answer than a headline claiming that correction is always mandatory.

The application covered two different events. In the first, the due date on the invoice did not match the arrangements already in place when the invoice was issued. In the second, the invoice was correct when issued, but the parties agreed a new due date later.

In both cases, the invoice had been issued through KSeF and the change did not affect the taxable amount, VAT or gross receivable. The question concerned only how the new payment date should be documented.

The company believed that neither scenario required a corrective invoice. Its argument relied in part on the fact that the payment due date is not one of the mandatory invoice items listed in Article 106e(1) of the Polish VAT Act.

This was the applicant's position, not the authority's conclusion. The distinction is essential because the Director of National Tax Information formally found the company's position to be incorrect.

The Director of National Tax Information found the company's position to be incorrect. The authority relied on Article 106j(1)(5) of the VAT Act, which provides for a corrective invoice when an error is found in any invoice item.

The authority interpreted an invoice item broadly. It included additional information such as the payment due date and therefore indicated a corrective invoice as the proper method in both the original-error and later-change scenarios.

For a structured invoice, Article 106j(4) provides for the correction to be issued as a structured invoice or as an invoice issued in offline24 mode under Article 106nda(1). The accepted original is not edited in the system. A separate invoice referring to the original is issued instead.

The most important nuance appears in the reasoning itself. On one hand, the authority rejected the company's position and indicated correction as the proper method. On the other, it wrote that the taxpayer may and should issue a corrective invoice, but is not obliged to do so.

The authority added that correcting optional invoice information is not the seller's obligation, although it is expected when the additional data is material to the parties. A payment due date will usually matter because it affects receivables, collection activity and the assessment of late payment.

The safe conclusion is therefore that correction is the method indicated by the authority for a due date shown on an invoice, but this one interpretation should not be turned into an unconditional obligation covering every commercial change.

Article 106e(1) of the VAT Act lists the mandatory invoice items but does not include the payment due date. The FA(3) structure also treats the payment and due-date section as optional.

Optional means that omitting the information does not by itself make the invoice incomplete. It does not mean that information entered voluntarily may remain inconsistent with the parties' arrangements without any documentary consequence.

This distinction underpins the authority's reasoning. The date does not have to appear on the invoice, but if it is entered and matters to settlement, it should reflect the actual arrangements.

An agreement, email or contract amendment exists outside KSeF. It can evidence a postponed payment date if the method of agreement complies with the contract, representation rules and any applicable form requirement. KSeF is not used to create such agreements.

A separate issue is whether the invoice remains consistent with the new arrangements. If the original invoice contains a specific due date, the interpretation indicates a correction as the way to update that information. The external agreement documents the basis of the change, while the corrective invoice puts the KSeF document in order.

If the due date never appeared on the invoice, the later agreement does not change an existing invoice item. The 2026 interpretation does not directly decide this scenario, so its conclusion about a date already shown should not be transferred automatically.

Start by checking the document's status. In a standard online submission, a draft, a rejected file and an invoice accepted with a KSeF number represent different stages of the process.

An invoice accepted by KSeF cannot be edited or deleted. If its due date needs to be corrected, the authority indicated a separate corrective invoice as the proper method. For a rejected file, first confirm the final status and exclude the possibility that an earlier submission of the same document was accepted. Only then correct the data and retry the standard online submission.

The standard online rule is not sufficient for offline24 because an invoice in that mode may already have been issued before it is sent to KSeF. If you are unsure whether KSeF accepted the document, do not create a correction or resubmit it based solely on an application message. Check the final status, KSeF number and UPO first. See How to check an invoice status in KSeF for the relevant control points.

A correction to an ordinary sales invoice uses the KOR type in FA(3). In the scenario analysed, the correction should state the issuer's number and date of the corrected invoice as well as its KSeF number, because the original was accepted by the system. The correct content of the corrected information must then be provided.

The new date is entered in the FA(3) payment and payment-due-date section. The schema allows either a specific date or a description of the term. Stating the reason for correction is optional under Article 106j(2a), but a clear explanation helps accounting staff and the counterparty understand the document.

Do not mechanically treat a date-only change as a value correction. First confirm that the line items, taxable amount, VAT and gross receivable do not change. If the new term has another economic effect, the document may need a broader scope.

After preparing the document, validate it, send it to KSeF and verify its status and UPO. The general process is explained in Corrective invoice in KSeF.

In the circumstances described in the application, changing the due date did not affect the taxable amount, VAT or gross value. The correction put information relevant to receivables in order rather than changing output tax.

This neutrality should not be extended to every case. A postponed payment date may be linked to an early-payment discount, other discount, interest or another economic term. In that situation, assess separately whether the invoice values and the time at which the correction is recognised also change.

The 2026 letter did not arise in isolation. Earlier interpretations reached different conclusions, but they concerned different law and facts. They should not be compared without those reservations.

In 2019, the authority treated the due date as additional information that the seller should not change through a corrective invoice and referred to a correction note issued by the buyer. That method is now only of historical importance. No new correction notes have been issued since February 1, 2026, while transitional rules apply to notes issued before that date.

The 2013 case concerned a date that was correct when the invoice was issued and was later extended by agreement in the context of bad debt relief. The authority did not see a mandatory correction at that time. The difference therefore primarily concerns mandatory correction and the context of the case, not an identical KSeF model.

An individual interpretation generally protects the applicant if the actual conduct corresponds to the facts or future event described in the application. It is neither a court judgment nor a source of generally applicable law.

For other taxpayers, the letter is a useful signal of the authority's current reasoning. If your circumstances differ materially, for example because no due date appeared on the invoice or postponement is connected with a discount, the case needs a separate assessment.

Before issuing a correction, answer eight questions: does the date appear on the invoice, was it wrong from the start, when did the parties agree the change, what evidence records the agreement, does the invoice have a KSeF number, do any amounts change, does the correction identify the original correctly, and did the submission result in the correct status and UPO?

If the answers point to an accepted invoice with a due date different from the agreed date, the interpretation of July 10, 2026 supports issuing a corrective invoice. If the change concerns only arrangements outside the invoice, do not extend that conclusion automatically.

The greatest risk is not the selection of the document type itself. It arises when a business fails to distinguish the effectiveness of an agreement between the parties from the accuracy of information shown on the invoice.

A sound procedure should preserve two audit trails. The first shows why the date was changed and who accepted the new terms. The second shows how the invoice content was put in order after KSeF accepted it.

The ambiguity in the reasoning supports a risk-based approach. When the date appears on the invoice and affects receivables, a correction is the cautious method and is consistent with the formal conclusion. When the date exists only outside the invoice, a separate assessment is needed instead of automatically creating another document.

For high-value cases or a dispute with a counterparty, agree the approach with accounting staff or a tax adviser. One individual interpretation does not remove every doubt created by its own reasoning.

KSeFGPT does not replace a tax decision, but it helps complete the subsequent process in one place. You can work with the source invoice and correction, check data completeness, monitor submission status and retain the KSeF number and UPO.

First agree with accounting staff whether a correction should be issued in the specific case. Then ensure that the documents are linked correctly and verify the submission result. The KSeFGPT Invoices module helps prevent data from being scattered across email, spreadsheets and separate folders.

To explore payment terms, document types and the invoice structure further, read:

KSeF invoice payment term - explains how to distinguish the issue date, receipt date and payment due date.

Corrective invoice in KSeF - covers the general process for issuing and submitting corrections.

Invoice types in KSeF - organises the document types available in the FA(3) structure.

XML and the FA(3) format in KSeF - shows how invoice data is recorded in a structured document.