Rules / PEPPOL-EN16931-R080 · Markdown
PEPPOL-EN16931-R080
PEPPOL BIS Billing 3.0 layer: peppol
Checked against Peppol BIS Billing 3.0 2026.5
What does PEPPOL-EN16931-R080 mean? Only one project reference is allowed on document level
Why did my invoice fail PEPPOL-EN16931-R080?
At most one Project reference (BT-11) may appear at the document (invoice) level. EN 16931 models the project reference as a single business term, so multiple ProjectReference elements on the header are not permitted.
Official rule text
Only one project reference is allowed on document level
Common causes
- The invoice carries several cac:ProjectReference elements at document level instead of one.
- Multiple project identifiers from different source systems were all mapped to header ProjectReference.
- A per-line project code was mistakenly duplicated onto the document header.
How do I fix it?
Keep a single header reference: <cac:ProjectReference><cbc:ID>PRJ-2026-17</cbc:ID></cac:ProjectReference> and remove any additional ProjectReference elements.
Related rules
PEPPOL-EN16931-R001 · PEPPOL-EN16931-R002 · PEPPOL-EN16931-R003 · PEPPOL-EN16931-R004 · PEPPOL-EN16931-R005 · PEPPOL-EN16931-R007 · PEPPOL-EN16931-R008 · PEPPOL-EN16931-R010
Check your invoice against this rule
Paste it into the live demo, or call POST /v1/validate. See the quickstart.