UBL-SR-52
EN 16931-1 layer: en16931
Checked against Peppol BIS Billing 3.0 2026.5
What does UBL-SR-52 mean? Document reference shall occur maximum once
Why did my invoice fail UBL-SR-52?
This rule limits a referenced document (such as an Additional supporting document BG-24, an Invoiced object identifier, or a preceding invoice reference) to a single instance of the reference detail. Within one cac:...DocumentReference, the identifying/description element may occur at most once. This keeps each document reference well-formed and unambiguous.
Official rule text
Document reference shall occur maximum once
Common causes
- A DocumentReference block repeats the same detail element (e.g. two cbc:DocumentDescription).
- Attachment metadata was written twice inside one cac:AdditionalDocumentReference.
- Duplicated reference elements were produced when merging supporting-document data.
How do I fix it?
Keep one detail per reference, e.g. a single <cbc:DocumentDescription>Timesheet April 2026</cbc:DocumentDescription> inside the cac:AdditionalDocumentReference; add a separate DocumentReference for a genuinely different document.
Related rules
UBL-SR-01 · UBL-SR-02 · UBL-SR-03 · UBL-SR-04 · UBL-SR-05 · UBL-SR-06 · UBL-SR-07 · UBL-SR-08
Check your invoice against this rule
Paste it into the live demo, or call POST /v1/validate. See the quickstart.