DE-R-015
If both supplier and customer are located in Germany, the element "Buyer reference" (BT-10) shall be provided.
error: the document is invalid
Peppol documentation ↗
What the rule checks
As the rule set's publisher wrote it. The rule runs on every element the context matches, and fails where the test is false; the validator reports the line of that element.
Context
(/ubl-invoice:Invoice | /ubl-creditnote:CreditNote)[$supplierCountryIsDE and $customerCountryIsDE]
Test
cbc:BuyerReference[boolean(normalize-space(.))]
Checked with Peppol BIS Billing 3.0 Invoice, Peppol BIS Billing 3.0 Credit Note