E-Invoice ValidatorBT-24 — specification identifier
The field that says which rules the invoice should be checked against.
BT-24 is the identifier of the set of rules according to which the invoice was created - for example urn:cen.eu:en16931:2017 for the European basic standard or an XRechnung or Peppol identifier.
In UBL it is in cbc:CustomizationID, in CII in GuidelineSpecifiedDocumentContextParameter. Without BT-24 it is not possible to decide which additional rules apply - which is why it is always mandatory.
The validator first reads BT-24 and then selects the rule sets. An incorrect or outdated identifier causes the wrong rules to apply.
Rules that often fail here
See also
Status: 12.10.2026