Validation rules

BR-CL-24 — EN 16931 rule

The MIME type of an embedded attachment (BT-125 mimeCode) is not one of the types EN 16931 permits (PDF, PNG, JPEG, CSV, XLSX or ODS).

Rule

BR-CL-24 — official EN 16931 / XRechnung rule

Severity

error

Detected by

tier 3 — KoSIT validator (authoritative)

Reachability

Not expressible through the normbill invoice model — documented for completeness

supporting_documents[i].mime_type is a closed Zod enum of the six permitted MIME types, so unknown values never reach the serializer. Fatal in the primary CIUS scenario (only the Extension scenario downgrades it).

How to fix it

Use one of the permitted MIME types on cbc:EmbeddedDocumentBinaryObject, e.g. "application/pdf".

Related rules

• BR-CL-25 — An electronic address scheme (BT-34 seller, BT-49 buyer — the schemeID on cbc:EndpointID) is not part of the…
• BR-CL-23 — A unit code (BT-130 invoiced quantity, BT-150 price base quantity) is not part of UN/ECE Recommendation…
• BR-CL-22 — A VAT exemption reason code (BT-121) is not part of the VATEX code list.
• BR-CL-26 — The scheme of a delivery location identifier (BT-71 schemeID) is not part of the ISO/IEC 6523 ICD list.
• BR-CL-21 — The scheme of an item standard identifier (BT-157 schemeID) is not part of the ISO/IEC 6523 ICD list.
• BR-CL-20 — A charge reason code (BT-105 document level, BT-145 line level) is not a UNTDID 7161 code.

Official sources

• XRechnung specification (KoSIT / xeinkauf.de)
• KoSIT validator on GitHub and the XRechnung validator configuration

Every 422 from the API lists the rule id, the path in your request JSON, a plain-language message and a suggested fix — see the docs overview for the report format.

Or try it live: drop any XRechnung XML on the free validator — same KoSIT-backed report, no account.