- The newly introduced “Attachment” node in the KSeF invoice structure allows for the inclusion of character values within structured invoices but does not permit the sending of external files, such as PDF specifications, via KSeF.
- Invoices utilizing the “Attachment” node can only be issued for activities with complex data requirements, as specified in Article 106gba(1) of the VAT Act, and the use of this node is not limited to any specific industry.
- Taxpayers must notify the Head of the National Tax Administration via the e-Tax Office before issuing invoices with the “Attachment” node, and such invoices can only be submitted through commercial tools integrated with the KSeF API, not via free tools provided by the Ministry of Finance.
Source: mddp.pl
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- See also
- Join the Linkedin Group on Global E-Invoicing/E-Reporting/SAF-T Developments, click HERE
- Join the LinkedIn Group on ”VAT in the Digital Age” (VIDA), click HERE
See also KSeF 2.0 Part III manual
Summary in English
The document explains additional functionalities of the Polish National e‑Invoicing System (KSeF) as of 1 February 2026, focusing on attachments, self‑billing, offline modes, collective payment identifiers, abuse reporting, invoice hiding, and VAT RR invoices.
Scope of the manual
- The manual describes new and extended KSeF 2.0 functions: invoice with attachment, self‑billing (including with EU counterparties), offline/backup modes, total outage, collective payment identifiers, “scam” invoice reporting, hiding purchase invoices, and VAT RR invoices.
- It is based on the legal state as of 1 February 2026 and refers to the amended VAT Act and the new regulation on the use of KSeF.
Invoice with attachment (Faktura z załącznikiem)
- From 1 February 2026, KSeF 2.0 allows issuing and sending e‑invoices with a structured XML attachment (element “Zalacznik” in FA(3)), mainly for transactions with complex data on units of measure, quantities or unit prices (e.g. utilities, telecoms, fuel).
- The attachment is an integral part of the XML invoice and may only contain data required by article 106e(1) VAT Act or data closely linked to those; marketing, commercial or contractual documents (price lists, contracts, guarantees, newsletters, etc.) are explicitly excluded.
Notification to use / stop using attachments
- Taxpayers who want to use invoices with attachments must submit an electronic notification via the e‑Tax Office (e‑Urząd Skarbowy), not via KSeF API, Taxpayer App, mobile app, e‑mikrofirma or paper.
- The notification indicates NIP, contact details, type of transactions, planned start date and estimated volume/size; KAS confirms activation within up to 3 working days via e‑mail and the right is granted for an indefinite period.
- A separate notification is used to declare cessation of issuing invoices with attachments; after its technical processing (again within up to 3 working days), the ability to issue any invoice with attachment, including corrective invoices, is removed.
Withdrawal of the attachment functionality by KAS
- KAS may revoke the possibility to issue invoices with attachment if attachments contain non‑permitted data or are used contrary to article 106gba (e.g. moving mandatory FA(3) fields into the attachment only).
- In such cases, taxpayers may still issue KSeF invoices without attachment and may re‑apply for the functionality, but repeated breaches can lead to repeated withdrawals; attempts to send an invoice with attachment without this right will trigger an error and rejection.
Self‑billing in KSeF (Samofakturowanie)
- The manual explains procedures for approving invoices under self‑billing, direct and indirect authorisations, how self‑billing fits into FA(3), and how access to such invoices is managed.
- It also covers self‑billing when the counterparty is an EU entity, including the role of an EU administrator, designated persons, a combined NIP‑VAT EU identifier and specific KSeF numbering in these cases.
Offline, emergency and total outage modes
- KSeF 2.0 introduces:
- “offline24” mode (specific offline procedure),
- an offline mode for system unavailability, and
- an emergency mode, plus a separate “total outage” regime.
- For each mode, the manual details: who may use it, legal basis, practical steps, invoice issuance and receipt dates, use of two QR codes/links on the invoice, issuing “transaction confirmations” and rules for corrective invoices; a technical section explains XML corrections and the interface informing about KSeF failures.
Collective payment identifier
- A “collective identifier” can be used in payments between active VAT taxpayers to link payments to multiple structured invoices; the manual describes payment flows using this identifier and the separate identifier used in split‑payment transfer messages (MPP).
- It explains how to generate, structure, decode and search these identifiers in relation to specific invoices and contexts.
Abuse report – “scam” invoice
- Taxpayers can report suspected abusive or fraudulent invoices (“faktura scamowa”) in KSeF; the manual describes who can report, in what situations, how to submit a report, how the tax administration verifies it, how a report can be withdrawn and the status types assigned to reports.
Hiding purchase invoices
- KSeF allows hiding a purchase invoice from the user’s standard view; the manual sets out who may hide an invoice, in which situations, how to hide and restore visibility, and the different visibility statuses.
VAT RR and VAT RR correction invoices
-
A dedicated chapter covers issuing VAT RR and VAT RR correction invoices in KSeF, including authorisation models (direct, indirect, special models), modes of issuance, handling outages, two‑step and anonymous access with a QR code, corrective invoices and storage rules.
-
It notes that VAT RR invoices do not use the invoice‑with‑attachment functionality (no attachment in FA_RR(1)) and explains the technical aspects of issuing them in KSeF, including when the flat‑rate farmer is the purchaser and does not have a NIP.
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