- KSeF 1.0 and the Module of Certificates and Authorizations (MCU) will be unavailable from 26-31 January 2026 for technical maintenance.
- 25 January 2026 is the last day to generate KSeF certificates, tokens, or assign authorizations via MCU.
- KSeF 2.0 API will be available for verification in the production environment from 28 January 2026.
- KSeF 1.0 and MCU will be permanently discontinued on 1 February 2026, with KSeF 2.0 becoming the only mandatory system.
- From 1 February 2026, all certificate and token generation must be done through the KSeF 2.0 Taxpayer Application; ZAW-FA forms can be submitted during the maintenance break for basic authorizations.
Source: sovos.com
Note that this post was (partially) written with the help of AI. It is always useful to review the original source material, and where needed to obtain (local) advice from a specialist.
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