# OIOUBL

Danish UBL CIUS used by NemHandel; OIOUBL 3 (released 2024) aligns with EN 16931.

## Definition

Danish UBL CIUS used by NemHandel; OIOUBL 3 (released 2024) aligns with EN 16931.

## Explanation

OIOUBL 2.x predates EN 16931 and adds Danish-specific extensions; OIOUBL 3 maps onto EN 16931 + Peppol BIS Billing.

Validators are published by the Danish Business Authority and run by NemHandel before delivery to public-sector recipients.

## Related resources

- [Denmark e-invoicing guide](/resources/countries/denmark)

## Related terms

- [NemHandel](/resources/glossary/nemhandel): Danish national e-invoicing infrastructure built around OIOUBL and now interoperating with Peppol.
- [CIUS](/resources/glossary/cius): Country or sector specific usage specification that constrains EN 16931.
- [UBL](/resources/glossary/ubl): Universal Business Language: an XML library for standard business documents.
- [PEPPOL BIS](/resources/glossary/peppol-bis): Business Interoperability Specifications defining document rules (commonly BIS 3.0 for invoices).