Poland Finalizes Transition to KSeF 2.0 and Shut Downs KSeF 1.0
The Polish Ministry of Finance has completed the migration to the KSeF 2.0 production environment, marking the official launch of the mandatory e-invoicing era in Poland. Following a technical maintenance period at the end of January, the updated National e-Invoicing System is now the mandatroy platform for digital tax documentation.
Technical Transition and KSeF 1.0 Shutdown
To facilitate the deployment of KSeF 2.0, the Polish Tax Authority conducted a scheduled technical break from January 26 to January 31, 2026. During this time, the legacy KSeF 1.0 system and the Certificate and Authorizations Module (MCU) were taken offline for infrastructure upgrades.
While the system was largely inaccessible, the Ministry provided a verification window beginning January 28, 2026, during which the KSeF 2.0 API was available in the production environment. This allowed businesses and service providers to perform final checks of user authentication protocols, permission lookups, authorization views, token generation, and certificate retrieval.
The transition followed a strict schedule:
- January 25, 2026: Final day to generate tokens or grant authorizations via the legacy MCU.
- January 26–31, 2026: Full technical maintenance break for KSeF 1.0 and MCU components.
- January 28, 2026: Production API opened for system verification and handshake testing.
- February 1, 2026: KSeF 2.0 Go-Live: Mandatory use begins for large enterprises.
As of February 1, 2026, KSeF 1.0 has been permanently discontinued. This means that authentication tokens or certificates generated under the 1.0 system are no longer valid for production use. Taxpayers must now issue credentials using the KSeF 2.0 Taxpayer Application.
There’s more you should know about e-invoicing in Poland – learn more about the new and upcoming regulations.
