One wrong digit in a buyer NIP and your invoice sits in the KSeF account of a company you have never traded with. Until January 2026 this was a two-minute problem. The buyer issued a corrective note (nota korygująca), the seller accepted it, done.
That route no longer exists. If your group runs a Polish subsidiary or you invoice Polish counterparties, this changes who owns the fix and when it hits your VAT return. Below is the procedure, the technical reason behind it, and the cases it does not cover.
What disappeared on 1 February 2026
The act of 5 August 2025 introducing mandatory KSeF (Poland's national e-invoicing system), published as Dz.U. 2025 poz. 1203, repealed Article 106k of the VAT Act. That provision let the buyer correct formal details on a received invoice: its own name, address and NIP.
The repeal is absolute. Corrective notes cannot be issued inside KSeF, outside KSeF, against structured invoices or against paper ones. Asking the seller to accept such a document changes nothing, because acceptance of an instrument the statute no longer recognises does not create a correction invoice.
Only historical documents keep their status. A note issued before 1 February 2026 is judged under the rules in force on its issue date, so a January note accepted in March remains valid.
From that date the burden sits entirely with the seller. The legal hook is Article 106j(1)(5) of the VAT Act: a correction invoice is required whenever an error is found in any item of an issued invoice.
Why zeroing, rather than a simple data fix
This part is worth understanding, because the procedure looks heavier than the error.
Once KSeF accepts a structured invoice it assigns a KSeF number, and the document becomes available to whoever holds the NIP written on it. If that NIP belongs to a real business, the invoice is already sitting in their account. You cannot pull it back, because a structured invoice cannot be cancelled.
The FA(3) logical structure also has no mechanism for a correction that rewrites the buyer's tax identification fields. A correction points at one specific document issued to one specific party. Changing the NIP would mean correcting an invoice that was issued to somebody else.
So the Ministry of Finance, in the KSeF 2.0 Manual published at ksef.podatki.gov.pl, sets out a single valid path: the seller zeroes the faulty invoice with a correction, then issues a new original invoice to the correct buyer. The Director of the National Revenue Information Service confirmed this in a 2026 binding ruling that referenced the Ministry's explanations directly.
One detail catches people out. The zero correction must carry the same wrong NIP as the original invoice. It corrects a document issued to that entity. The correct NIP appears only on the new invoice.
Step by step
Step Document Buyer NIP Amounts 1 Original invoice (already in KSeF) wrong full 2 Zero correction (KOR) wrong, same as step 1 zero 3 New original invoice correct full
Step 1. Scope the error. Check whether the NIP exists and who holds it. If it belongs to a real company, tell them a document arrived that is not theirs and warn them a correction is coming.
Step 2. Issue the zero correction. Every line drops to zero: quantity, unit price, net, VAT, gross. State a specific reason, for example "incorrect buyer NIP on the original invoice". Send it to KSeF.
Step 3. Issue the new original invoice. Same lines, same amounts, same supply date, correct buyer. This is not a new transaction, it is correct documentation of the same supply.
Step 4. Book both retroactively. The zero correction and the new invoice both belong in the accounting period of the original invoice. The correction does not stem from a change in the taxable base or the tax amount, so there is no basis for current-period treatment.
The net effect is neutral. One period holds the original invoice, its reversal and the replacement, leaving a single real taxable supply to the correct buyer. The Ministry of Finance has stated explicitly that this path does not create temporary double reporting of output VAT.
What this rule does not cover
Zeroing is the remedy for a NIP error, not for every mistake.
A typo in the buyer's name or a stale address with a correct NIP does not need zeroing. The document reached the right entity, so an ordinary correction of formal details is enough. Zeroing here means three documents where one would do.
Invoices issued outside KSeF follow the same rule on corrective notes: they are gone. But the technical constraint that forces zeroing applies to a document that already exists in the system under a stranger's account. Outside the system, correcting identification data remains workable.
Invoices issued in offline24 mode reach KSeF with a delay. Catch the error before transmission and you simply fix your own document. Once a KSeF number is assigned, the full procedure applies.
B2C sales without a buyer NIP never hit this problem.
How this works in Biurko
In Biurko the zero correction is a single action on the invoice. You click "Correct to zero", the system creates a draft KOR document, copies every line with zeroed amounts and carries over the buyer details from the original, including the wrong NIP. Nothing to retype, and no risk of quietly "fixing" the NIP inside the correction itself.
The replacement invoice does not need retyping either. Duplication copies lines and settings from the original, and you change only the counterparty. A NIP lookup against the Polish business register (GUS) pulls official registration data, which makes a repeat of the same error less likely.
Only one draft correction can exist per invoice at a time. Click the action twice and you land back in the existing draft rather than generating a second document. In an accounting office with several people touching the same client, that guardrail saves a lot of explaining.
Checklist for a wrong NIP
Check whether the wrong NIP belongs to a real entity and notify them.
Issue the zero correction carrying the same wrong NIP.
Write a specific reason, not a generic "error".
Send the correction to KSeF and wait for the KSeF number and the UPO (official receipt confirmation).
Issue the new original invoice with the correct NIP and the same supply date.
Book both documents in the original invoice's accounting period.
Keep a note linking the three documents for audit purposes.
Summary
Removing corrective notes moved full responsibility for data accuracy onto the issuer. A wrong buyer NIP stopped being a formality and became a three-document procedure. The upside is that the procedure is predictable, which means it can be automated.
Biurko generates the zero correction in one click, keeps buyer data consistent across the chain and sends both documents to KSeF with a full audit trail. Create a free account at biurko.io and walk through the procedure on a test invoice before you need it under pressure.
FAQ
Can I still issue a corrective note for a 2025 invoice? No. What matters is the date of the corrective act, not the date of the original invoice. Since 1 February 2026 the enabling provision no longer exists, so every fix requires a correction invoice from the seller.
Who issues the zero correction, the seller or the buyer? The seller only. After the repeal of Article 106k the buyer has no instrument for self-correction. Their role is to report the error and wait for the documents.
Does the zero correction plus a new invoice mean paying VAT twice? No. Both documents are booked in the original invoice's accounting period, leaving one taxable supply in the return. The Ministry of Finance has confirmed the procedure does not breach VAT neutrality.
Which NIP goes on the zero correction? The wrong one, identical to the original invoice. The correction refers to a specific document issued to that entity. The correct NIP appears only on the new original invoice.
Does a wrong company name with a correct NIP also require zeroing? No. If the NIP is right, the invoice reached the right entity and a correction of formal details is sufficient. Zeroing applies where the document physically landed in a stranger's KSeF account.
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