What is EN 16931 and what does version 2026 bring?
Short answer
EN 16931 is a European standard that defines the semantic data model of an electronic invoice: data, their meaning and business rules. It does not, by itself, specify a specific XML notation or delivery network; syntax is ensured by, for example, UBL or CII, and other rules are added by Peppol BIS or national implementation. EN 16931-1:2026 was published in May 2026 and the 2017 version has been formally withdrawn but remains compliant during the migration period. Therefore, the Slovak implementer should not arbitrarily switch the ERP to a new version, but follow effective validation artifacts and the schedule of the Financial Administration and Peppol Authority of the Slovak Republic.
What the invoice must contain
EN 16931 defines mandatory and optional Business Terms and their meaning.
XML addresses other standards
UBL or CII ensure specific writing in XML.
BIS Billing 3.0
Peppol BIS Billing adds its own implementation and validation rules on top of EN 16931.
There is no tax assessment
The standard does not verify the correctness of the VAT regime or the business case.
Conclusion
EN 16931 determines the content and meaning of electronic invoice data; the recording format (UBL/CII) and the delivery method (e.g. Peppol) are handled by another layer of standards.
European Commission - European Standard and Specifications · register of supporting artifacts EN 16931
Not legal advice. Machine-translated answer, not yet manually reviewed. For the exact wording, see the Slovak original.