Published: January 2026
As part of preparations for the implementation of KSeF 2.0, the Polish Ministry of Finance has confirmed a planned technical maintenance break affecting the current KSeF 1.0 system. The downtime is scheduled to take place between 26 January and 31 January 2026 and will also cover the Certificate and Authorizations Module (MCU).
During this period, the MCU will be fully unavailable. As a result, taxpayers will no longer be able to generate production tokens, download certificates, or grant authorizations via KSeF 1.0. The authorities have confirmed that 25 January 2026 (inclusive) will be the final day to complete these actions under the existing system.
The transition will culminate on 1 February 2026, when KSeF 2.0 becomes the sole operational system and KSeF 1.0, together with the MCU, permanently ceases to function. From that date, certificates, tokens, and authorizations will again be available—this time via the KSeF 2.0 Taxpayer Application.
Additionally, from 28 January 2026, the KSeF 2.0 API will be accessible in the production environment for verification purposes, including authentication, permissions, token generation, and certificate-related processes. Businesses are therefore strongly advised to complete all necessary setup activities ahead of the announced downtime to avoid operational disruptions.
