- On December 22, 2025, the production contract for API KSeF 2.0 will be frozen by the Ministry of Finance.
- The API will remain stable, with only optimizations and clarifications allowed that do not require major changes for integrators.
- Key elements like endpoints, request/response formats, field meanings, response codes, and validation rules will remain unchanged.
- The API version naming will drop the “RC” (Release Candidate) label, but this does not affect functionality.
- From December 22, 2025: API will return only UPO v4-3, `subjectDetails` becomes mandatory, and the query period for metadata and invoice export is reduced from 2 years to 3 months.
Source: gov.pl
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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