Poland's KSeF 2.0 Transition: Critical Timeline Updates for 2025-2026

Poland's Ministry of Finance has officially announced the transition timeline from KSeF 1.0 to KSeF 2.0, marking a crucial phase in the country's mandatory e-invoicing implementation. With the KSeF 1.0 Test environment already shut down on September 1, 2025, businesses now face a clear roadmap toward mandatory compliance beginning February 1, 2026.

Key Transition Milestones

The transition follows a carefully structured timeline designed to ensure smooth implementation:

September 30, 2025: The KSeF 2.0 Test environment launches, enabling open API testing for software providers and integrators. This marks the first opportunity for businesses to test their systems with the new platform since the KSeF 1.0 Test environment closure.

October 15, 2025: The Pre-production (Demo) environment opens, allowing businesses to begin API connections and integration testing in a controlled environment.

November 1, 2025: The new Certificates and Permissions (MCU) module launches, enabling enhanced permission management and facilitating KSeF certificate submission and download processes.

November 3, 2025: The KSeF Taxpayer App becomes available in the Test environment, followed by Demo environment availability on November 15, 2025

Production Environment Changes

The most significant changes occur in early 2026:

January 26, 2026: The KSeF 1.0 Production environment will be discontinued, ahead of a planned maintenance window running through January 31, 2026.

February 1, 2026: The KSeF 2.0 Production environment goes live, coinciding with the mandatory compliance date for large taxpayers (those with 2024 sales exceeding PLN 200 million).

Critical Testing Gap

Businesses should note that testing capabilities are currently unavailable and will remain so until September 30, 2025. This creates a critical window where companies cannot test their systems, making the September 30 launch date particularly important for organizations preparing for compliance.

Business Impact and Preparation

The transition to KSeF 2.0 introduces enhanced API capabilities designed to streamline integration and improve system performance. The Ministry of Finance has already published comprehensive API documentation to support integrators in preparing their systems for the transition.

Companies should prioritize:

• Immediate preparation for September 30 testing opportunities

• Early engagement with software providers to ensure KSeF 2.0 compatibility

• Resource allocation for testing and integration during the critical October-November period

• Staff training on new system requirements and procedures

The KSeF 2.0 upgrade represents more than a technical update—it's the foundation for Poland's mandatory e-invoicing mandate that will affect all VAT-registered businesses by April 1, 2026.

fiscal-requirements https://ksef.podatki.gov.pl/ksef-na-okres-obligatoryjny/wsparcie-dla-integratorow/