Poland’s KSeF 2.0 - the official e-invoicing mandate

Poland's business-to-business (B2B) electronic invoicing mandate has been a hot topic for several years, and recently, crucial changes have been introduced. Have you been able to keep up with these changes? Let's take a look at a concise summary of these key developments.

Poland’s KSeF mandate enters a new era

Poland's journey towards mandatory B2B e-invoicing has been a dynamic process involving numerous discussions and postponements. However, the landscape has now definitively shifted.

After President Karol Nawrocki signed the final legislation, the Krajowy System e-Faktur (KSeF) 2.0 mandate officially entered its next crucial phase. In the following, we will provide a comprehensive overview of the confirmed timelines, key technical and procedural changes, and the adaptation period to help ensure your business is fully prepared for the official launch.

KSeF 2.0: The legislative landscape and official launch

On 27 August 2025, the President of Poland, Karol Nawrocki, signed the final legislation for the KSeF mandate. This makes the previously discussed dates official, rather than being in the draft stage. His signature signals to the whole market that the electronic invoicing system is not up for discussion and will improve tax compliance by requiring businesses to issue e-invoices through a centralised platform. KSeF (Krajowy System e-Faktur) 2.0 is ready for implementation. The main KSeF go-live date is 1 February 2026.

Latest key changes and updates for KSeF 2.0

Let's delve into the details of these significant revisions, covering everything from technical adjustments to process enhancements and adaptation periods.

Technical environment updates

The initial KSeF 1.0 TEST environment was deactivated on 1 September 2025. To prepare businesses and software providers for the mandatory rollout, the Ministry of Finance will open KSeF 2.0 testing in two phases: open API testing begins on 30 September 2025, and integration with the pre-production (DEMO) environment will be possible from 15 October 2025.

Compared with the earlier 1.0 test system, KSeF 2.0 introduces a more stable infrastructure and updated API endpoints to reflect the new FA(3) invoice schema and validation rules (see below). Error messages and status codes have been standardised, which should make troubleshooting easier. Importantly, KSeF Certificates, required for live use from 1 February 2026, will be available for download starting 1 November 2025, giving users several months to configure their software and user accounts.

These updates are intended to give businesses and their ERP providers a smoother testing experience and to reduce last-minute integration issues once mandatory use begins.

Invoice structure and process enhancements

As already briefly touched on above, the transition from the Polish FA(2) to the FA(3) invoice structure will introduce significant changes at the process level. These updates are a direct result of feedback gathered from auditors, accountants, taxpayers, and software providers.

Key enhancements include:

• Structured attachments: KSeF FA(3) will now allow the inclusion of structured attachments as part of the e-invoice, such as contracts, delivery notes, claims, etc. 

• Expanded VAT rates: The list of VAT rates has been expanded with the addition of new classification codes.

Another important development is the “Offline24” mode. This new provision allows for issuing invoices when real-time connectivity to KSeF is unavailable, with later submission to KSeF. The key condition is that these invoices must be uploaded to KSeF no later than the end of the next day to receive their identifying number.

Adaptation period and penalty relief

To further support businesses in this transition, important provisions for adaptation and penalty relief have been introduced. For example, the obligation to include the KSeF invoice number in bank payments has been postponed until 1 January 2027, giving businesses more time to adapt their payment and accounting processes.

Additionally, the period without penalties for non-compliance with KSeF has been officially extended until the end of 2026, ensuring a smoother switch to the new way of reporting and e-invoice deliveries.

These measures underscore the commitment to facilitating a seamless transition to KSeF 2.0 before the phased rollout timelines commence.

Why early adoption still makes sense

Although the extended adaptation period and penalty relief offer flexibility, it’s important to note that delaying the implementation of KSeF nevertheless carries risks and means missing out on significant advantages. The absence of formal penalties in 2026 does not mean that postponement is entirely risk-free, particularly with regard to VAT compliance and income tax documentation.

One of the core purposes of KSeF is to establish a secure, standardised invoicing framework that provides a reliable digital audit trail for suppliers and buyers alike. This is essential for demonstrating due diligence under Polish VAT law. While buyers can currently deduct VAT from non-KSeF invoices during the grace period, these invoices lack KSeF's protective digital infrastructure. This could lead to a higher evidentiary burden for buyers during audits, potentially causing delays to VAT refunds or necessitating additional documentation. Consequently, businesses that delay KSeF implementation may face reputational and practical risks, as customers may question the security and legal protection of non-KSeF invoices.

Conversely, early adoption offers clear benefits:

• Enhanced security and compliance: By issuing invoices through KSeF from February or April 2026 (depending on your business's taxpayer category or mandate phase), businesses provide customers with a more secure document trail, reducing the risk of VAT deduction challenges and demonstrating a proactive approach to compliance.

• Operational advantages: One of KSeF's core operational advantages is its ability to streamline the invoicing process for businesses, minimising the need for paper records and ensuring consistency in invoice format and content. This can lead to faster VAT processing, fewer administrative errors, and a lower audit risk over time.

Therefore, although no short-term penalties are planned, delaying your KSeF implementation could nevertheless create real business disadvantages in terms of tax risk and customer relationships. Early adoption positions businesses for smoother operations and stronger compliance.

Phased rollout: Understanding the KSeF implementation timelines

The phased rollout dates for mandatory e-invoicing have been reconfirmed, remaining consistent with the timelines announced after the delay in April 2024:

• 1 February 2026:
  Mandatory for large taxpayers (2024 turnover exceeding PLN 200 million, or approx. € 47 million at the current exchange rate).

• 1 April 2026:
  Mandatory for all other businesses except the smallest micro-entrepreneurs deferred to 2027.

• 1 January 2027:
  Mandatory for micro-entrepreneurs with monthly sales under PLN 10,000, or approx. € 2,350. This later deadline, clarified in recent legislative updates, reflects additional flexibility granted to the smallest businesses, distinguishing them from the broader group mandated for April 2026.

Looking ahead

To successfully navigate these significant changes, businesses must prioritise understanding the KSeF 2.0 mandate and its implications. Although the adaptation period and penalty relief offer flexibility, adopting the new system early provides clear benefits in terms of compliance, operational efficiency and customer relationships. If you would like further guidance on ensuring your business is fully prepared for Poland's e-invoicing mandate, don’t hesitate to contact us.