fatal UBL
[DE-R-015]-If both supplier and customer are located in Germany, the element "Buyer reference" (BT-10) shall be provided.
(/ubl-invoice:Invoice | /ubl-creditnote:CreditNote)[$supplierCountryIsDE and $customerCountryIsDE]
cbc:BuyerReference[boolean(normalize-space(.))]
BT-10
BR-DE-15
Source: Peppol BIS Billing 3.0 Schematron, UBL (OpenPeppol, docs.peppol.eu validation artefacts 3.0.21).
Invoice XML (UBL 2.1 Invoice/CreditNote or UN/CEFACT CII D16B, max 5 MB):
Validate