The Polish Ministry of Finance (MoF) has published a technical communication providing additional details on the previously announced technical maintenance break for KSeF 1.0, scheduled for 26-31 January 2026, to allow the completion of the new version of the KSeF 2.0 system implementation.
What’s new?
The communication informs that the Module of Certificates and Authorizations (MCU) will be unavailable during the maintenance break, alongside KSeF 1.0 and its components. This means that 25 January 2026 is the last day for taxpayers to generate KSeF certificates, authentication tokens or assign authorizations through the MCU. Actions performed in the MCU apply to the KSeF 2.0 Production environment.
From 1 February 2026, generation of KSef certificates and tokens for the Production environment will be available via the KSeF 2.0 Taxpayer Application, according to previous communication of the MoF.
Additionally, the Ministry confirmed that KSeF 1.0 and the MCU will permanently cease to function on 1 February 2026. From that date, KSeF 2.0 will be the only available and mandatory system.
Key dates
|
Date |
Milestone |
|---|---|
|
25 January 2026 |
Last day to generate KSeF certificates/tokens or assign authorizations via the MCU |
|
26-31 January 2026 |
KSeF 1.0 and MCU unavailable (technical maintenance) |
|
28 January 2026 |
KSeF 2.0 API available on Production environment for verification |
|
1 February 2026 |
KSeF 2.0 go-live; KSeF 1.0 and MCU permanently discontinued |
What does this mean for taxpayers?
Taxpayers who have not yet generated KSeF certificates, authentication tokens or assigned authorizations via MCU, which applies to the KSeF 2.0 Production environment, should do so by end of day 25 January 2026. From 1 February 2026, granting permissions, tokens and KSeF certificates generation will be available through the KSeF 2.0 Taxpayer Application in relation to the KSeF 2.0 Production environment.
Additionally, during the maintenance break, taxpayers can still submit ZAW-FA forms to their local tax office to obtain basic KSeF authorizations, including administrative authorization for managing access in KSeF 2.0 from 1 February 2026.
Early access to KSeF 2.0 API
From 28 January 2026, the KSeF 2.0 API will be available on the production environment for verification purposes, allowing taxpayers and software providers to verify:
-
User authentication
-
Authorization lookup and viewing
-
Certificate applications and retrieval
-
Token generation
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