Marcin Chomiuk – Managing Partner at ADN Podatki Sp. z o.o. Marcin Chomiuk is a licensed tax advisor with nearly 30 years of experience, having gained professional expertise while working at Arthur Andersen and PricewaterhouseCoopers (PwC). During the last nine years at PwC, he served as a partner responsible for indirect tax consulting and led the advisory team for financial institutions. He has advised both major international corporations and local Polish companies. He is co-author of the first commentary on EU VAT regulations in the Polish market (the Sixth VAT Directive, now Directive 112) and has authored numerous publications in both professional and general press. He is also a co-author of the curriculum and lecturer for postgraduate tax studies at the Faculty of Law, University of Wrocław, and the Warsaw School of Economics (SGH). As an independent expert for the Polish Business Organization “Lewiatan,” he represented the interests of enterprises before the Ministry of Finance and parliamentary committees. He successfully won the landmark case BGŻ Leasing (C-224/11) before the Court of Justice of the European Union, concerning the VAT treatment of insurance services sold alongside leasing services, which reshaped the leasing market in Poland. Marcin has been recognized as one of the best VAT advisors in Poland.

1. Legal acts adopted and under legislative process concerning the mandatory KSeF.

2. New FA (3) invoice schema and FA_RR (1) invoice attachment.

3. Postponement of the mandatory KSeF go-live date to:
• 1 February 2026 – for entrepreneurs whose sales value (including tax amount) exceeded PLN 200 million in 2024,
• 1 April 2026 – for all other entrepreneurs.

4. Introduction of mandatory KSeF on the same date for VAT-registered taxpayers and VAT-exempt taxpayers, as well as adjustment of deadlines for the deferral of certain other solutions, including:
a. additional deferral until the end of 2026 of the obligation to provide the KSeF number in payments for e-invoices, including payments made under the split payment mechanism,
b. additional deferral until the end of 2026 regarding the possibility of issuing invoices via cash registers,
c. additional deferral until the end of 2026 regarding penalties for non-compliance with KSeF obligations.

5. Permanent implementation of the so-called “offline24 mode”, available to all taxpayers.

6. Regulation of consumer invoices by allowing them to be issued in KSeF and introduction of rules concerning the so-called “buyer self-identification” for the purpose of issuing an e-invoice by the supplier.

7. KSeF and invoices issued by local government units (LGUs) and the public sector:
a. additional mandatory, optional, and facultative fields in sections Party 1, Party 2, and Party 3,
b. ID WEW code – how to use it in the public sector?
c. dependent unit administrator – what is this role and when should it be applied?

8. Balancing obligations in KSeF between the issuer and the recipient, including the introduction of changes in income taxes to align invoice requirements as evidence of tax-deductible costs with KSeF conditions.

9. Introduction of the FA_RR (1) attachment to e-invoices in standard transaction types, covering an extended range of units of measure and prices of supplied goods or services.

10. Authorisations in KSeF:
a. authorisation tools (ePUAP, qualified electronic seal of the enterprise, qualified electronic signature, elimination of tokens),
b. appointment and revocation of the KSeF Master via ZAW-FA (content of the ZAW-FA notification, submission method and authorisation),
c. granting and revoking permissions for specific KSeF functions (delegation of permissions),
d. creation of dependent units in KSeF and administrators of such units.

11. Ensuring – prior to the start date of mandatory e-invoicing in KSeF – the ability to generate and download invoice issuer certificates used for issuing invoices in offline mode or during system outages (necessary for generating QR codes).

12. Ensuring, during the transitional period, that digitally excluded taxpayers with a low scale and value of issued invoices may continue issuing invoices in the traditional form (invoices up to PLN 450 outside KSeF).

13. Which documents will be generated in KSeF?:
a. VAT invoices and KSeF:
• standard invoice,
• simplified invoice,
• invoice with a limited data scope (e.g. tickets acting as invoices),
• invoices issued via cash registers,
• invoice issued to a receipt,
• advance invoice,
• re-invoice,
• VAT RR invoice,
• invoices issued by foreign taxpayers registered for VAT purposes in Poland,
• invoices issued to foreign contractors – will they need to be issued in KSeF?
• invoices received from foreign contractors,
• invoices issued to consumers,
• self-billing.
b. internal documents (WEW in JPK-VAT),
c. accounting notes (debit notes),
d. is it possible to issue documents other than invoices in KSeF?
e. invoice attachments in KSeF,
f. invoice duplicates (elimination of duplicates and cases where duplicates will still apply).

14. Content and form of the KSeF invoice – what does the structured invoice FA (3) look like?:
a. will the Ministry of Finance introduce changes to the content and form of the structured invoice (generated in KSeF) due to the postponement of KSeF implementation?
b. assumptions for the XML schema template for the FA (3) invoice and its individual fields (mandatory, optional, and facultative fields),
c. assumptions for the FA_RR (1) invoice attachment node and its individual fields (mandatory, optional, and facultative fields),
d. technical part of the structured invoice,
e. KSeF number – structure and meaning,
f. conversion of the structured invoice format (XML, PDF, HTML),
g. formal, substantive, and arithmetic verification of invoices in KSeF.

15. Issuing invoices in KSeF and tax obligation:
a. KSeF invoice issuance process,
b. preparation of invoice data,
c. invoice issue date in KSeF,
d. invoice issuance deadline under the VAT Act – does KSeF change anything?
e. submission of the invoice to KSeF,
f. authorisation of submission to KSeF (ePUAP, qualified electronic seal, qualified electronic signature, elimination of tokens),
g. invoice correctness verification by KSeF (validation),
h. feedback (UPO or rejection),
i. linking tax obligation with invoice dates,
j. exchange rates used in invoices and changes resulting from the KSeF package and offline mode.

16. VAT deduction – changes resulting from the KSeF package:
a. receipt of a structured invoice in KSeF (date of receipt in KSeF),
b. receipt of a structured invoice outside KSeF in paper or electronic form or in offline mode,
c. method of transferring a structured invoice outside KSeF,
d. QR code on a structured invoice,
e. access to structured invoices received in KSeF,
f. how to calculate payment deadlines for invoices received in KSeF?

17. Settlement of corrective invoices and correcting notes in KSeF:
a. invoice cancellation and KSeF,
b. corrective invoices in KSeF,
c. correction of structured invoices during the voluntary and mandatory KSeF periods,
d. correction of structured invoices exclusively in KSeF,
e. correction of invoices issued outside KSeF,
f. corrections of invoices outside KSeF – in which situations will this be possible?
g. can a traditional corrective invoice be issued for a structured invoice?
h. KSeF and downward/upward corrections of output VAT – timing of tax adjustment,
i. KSeF and downward/upward corrections of input VAT – timing of tax adjustment,
j. correcting notes and KSeF – elimination of regulations on correcting notes.

18. Emergency modes in KSeF (“offline” and “offline24” invoices):
a. KSeF system unavailability,
b. KSeF failure attributable to the tax authorities,
c. KSeF failure attributable to the taxpayer,
d. issue and receipt dates of offline invoices.

19. Privileges and sanctions resulting from KSeF:
a. 40-day VAT refund,
b. no obligation to provide sales invoices to tax authorities in the JPK_FA structure (no impact on JPK_WB, JPK_MAG),
c. no obligation for taxpayers to store invoices for 10 years,
d. facilitations regarding downward corrections for sellers and buyers,
e. facilitations in invoice delivery,
f. sanctions for failure to issue or submit invoices to KSeF.

20. KSeF and documentation in JPK_VAT:
a. KSeF system number and individual split payment transfers,
b. KSeF system number and collective split payment transfers,
c. KSeF system number and individual or collective standard transfers between VAT-registered taxpayers,
d. data reported in JPK and KSeF,
e. consistency between JPK_VAT and KSeF,
f. KSeF system number assigned to an invoice and its recognition in JPK_VAT,
g. structure of the KSeF number – information contained in the KSeF number,
h. should the KSeF system number be included on a structured invoice (issued in KSeF) provided to the buyer in paper or electronic form?