{
  "id": "UBL-SR-07",
  "country": "EU",
  "syntax": "ubl",
  "group": "syntax",
  "severity": "fatal",
  "severity_note": "fatal, from the Flag column of the Peppol BIS Billing 3.0 UBL rules index retrieved 2026-10-18.",
  "spec": "Peppol BIS Billing 3.0, May 2026 release, EN 16931 model bound to UBL",
  "statement": "If there is a preceding invoice reference, the preceding invoice number shall be present",
  "statement_lang": "en",
  "context": "cac:BillingReference",
  "test": "(cac:InvoiceDocumentReference/cbc:ID)",
  "meaning": "If a preceding invoice reference is present, the preceding invoice number shall be present. The statement has no period and says shall. The flag is fatal. The context is cac:BillingReference, not the invoice root. The published test is (cac:InvoiceDocumentReference/cbc:ID). It does not call count and it does not use <=.",
  "fix": "Give each invoice document reference inside a billing reference an identifier.",
  "example_fail": "A billing reference has an invoice document reference and that reference has no identifier.",
  "example_pass": "Each invoice document reference inside a billing reference has an identifier.",
  "example_note": "Illustration of the condition in the official statement. Not an example published by the source.",
  "source_url": "https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/UBL-SR-07/",
  "source_retrieved": "2026-10-18",
  "last_verified": "2026-10-18"
}