KSeF file limits create an unresolved obstacle for high-volume collective corrections

Summary

• The Polish tax authority maintains that a structured collective correction must include the required references to every corrected invoice directly in the FA(3) structure. Sending the detailed invoice list to the customer in an external attachment does not replace the statutory structured-data requirement. [edgp.gazetaprawna.pl], [es-doradztwo.pl]
• The difficulty becomes acute when a large correction exceeds KSeF’s technical limits. Publicly reported limits are 1 MB for an XML invoice without an attachment and 3 MB for an invoice with an approved KSeF attachment, yet the authority reportedly offered no alternative method for an oversized correction. [edgp.gazetaprawna.pl], [ksef.podatki.gov.pl]
• High-volume distributors and rebate-processing businesses should stress-test real data, quantify the maximum number of references per correction and redesign rebate settlement processes. Possible operational responses require legal validation because splitting one commercial adjustment into several KSeF corrections may affect numbering, period references, reconciliation and customer communication. [edgp.gazetaprawna.pl], [taxpoint.pl]

Extended article

Collective correction invoices are widely used for periodic rebates and other high-volume price adjustments. KSeF continues to permit such invoices, but the structured-invoice requirements can make them difficult to issue where thousands of original invoices are affected.

For each corrected invoice, the FA(3) structure may require details including the original issue date, taxpayer invoice number, an indication of whether the original document was issued in KSeF and, where applicable, its KSeF number. The relevant section must be repeated for each original invoice. An external spreadsheet or PDF may help the buyer reconcile the adjustment, but it does not replace the required information in the structured correction. [es-doradztwo.pl], [taxpoint.pl]

The reported interpretation concerned a wholesale distributor whose collective correction could exceed the KSeF limit. According to the publicly available article excerpt, the maximum XML size is 1 MB without an attachment and 3 MB where the invoice includes an approved KSeF attachment. The taxpayer proposed placing some required information in an external attachment sent outside KSeF. The Director of National Tax Information rejected that solution but did not identify an alternative way to satisfy the legal requirements within the technical limit. [edgp.gazetaprawna.pl]

It is important to distinguish between:

• a KSeF attachment forming an integral structured part of the invoice;
• an external business attachment sent by email or portal; and
• mandatory FA(3) invoice-reference fields.

Even the KSeF attachment functionality does not necessarily allow mandatory references to be moved out of the prescribed FA(3) nodes.

Businesses processing annual rebates should test production-level files rather than relying on a small demonstration dataset. Testing should account for long invoice numbers, KSeF identifiers, correction reason fields and character encoding.

Potential mitigations include issuing separate corrections for shorter sub-periods, customer divisions or defined invoice populations. However, any split must accurately reflect the rebate arrangement and meet the legal requirements applicable to each correction.

Recommended action: establish an automated pre-transmission file-size check and an escalation threshold well below the KSeF maximum. Obtain a documented legal position for the chosen splitting methodology.

Read the source article in Dziennik Gazeta Prawna and consult the official KSeF 2.0 functionality manual. [edgp.gazetaprawna.pl], [ksef.podatki.gov.pl]

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