UBL-SR-06
EN 16931-1 layer: en16931
Checked against Peppol BIS Billing 3.0 2026.5
What does UBL-SR-06 mean? Preceding invoice reference shall occur maximum once
Why did my invoice fail UBL-SR-06?
The Preceding invoice reference group (BG-3), which links a corrective or related invoice to the invoice it precedes, may occur at most once. In UBL this maps to cac:BillingReference/cac:InvoiceDocumentReference, and only one preceding invoice reference is permitted at header level in this profile.
Official rule text
Preceding invoice reference shall occur maximum once
Common causes
- A credit note or correction references several earlier invoices, each emitted as its own cac:BillingReference.
- The reference is duplicated in both an original and a re-mapped form.
- Loop over prior billing documents outputs multiple InvoiceDocumentReference blocks.
How do I fix it?
Keep a single reference: <cac:BillingReference><cac:InvoiceDocumentReference><cbc:ID>INV-2025-900</cbc:ID><cbc:IssueDate>2025-12-01</cbc:IssueDate></cac:InvoiceDocumentReference></cac:BillingReference> and remove the others.
Related rules
UBL-SR-01 · UBL-SR-02 · UBL-SR-03 · UBL-SR-04 · UBL-SR-05 · UBL-SR-07 · UBL-SR-08 · UBL-SR-09
Check your invoice against this rule
Paste it into the live demo, or call POST /v1/validate. See the quickstart.