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Warning

UBL-DT-26: Leave the encodingCode attribute out of the invoice

In short

Warning: worth checking.

UBL-DT-26 means the UBL file contains an encodingCode attribute, which the e-invoice standard does not use. It is only a warning, but you can fix it by exporting again without that attribute.

On this page

What it means

The rule searches the whole file for an attribute called encodingCode. In UBL it can be added to an element that holds a file, such as an attachment, to say how the content is encoded, for example Base64. The attribute should not appear anywhere in the invoice. The rule has no business term number because it is about how the XML is written, not about a field you fill in.

Why it matters

EN 16931 says you should leave the encodingCode attribute out of UBL invoices and credit notes.

How to fix it

You normally do not set this attribute yourself. Your invoicing software adds it when it writes the file, so look for an export setting or a newer version, or ask the software supplier to stop writing it. If you build the XML yourself, search the file for encodingCode and delete the attribute, typically from cbc:EmbeddedDocumentBinaryObject, then check the file again. It is worth fixing the next time you change your export, and sooner if a recipient asks for a file without warnings.

Once the file is corrected, check it again for free: Validate an invoice against EN 16931

Or fix the invoice in a form and download the corrected file, for 1 credit: Fix a rejected e-invoice

The rule as published

EncodingCode attribute should not be present

Where this rule applies

Rule set Version
EN 16931 (UBL) 1.3.17
EN 16931 (UBL credit note) 1.3.17
XRechnung 3.0 (UBL) 3.0.2
XRechnung 3.0 (UBL credit note) 3.0.2
Peppol BIS Billing 3.0 (invoice) 2026.5
Peppol BIS Billing 3.0 (credit note) 2026.5
SI-UBL 2.0 / NLCIUS (invoice) 2.0.3.13
SI-UBL 2.0 / NLCIUS (credit note) 2.0.3.13
France CTC (UBL invoice) 1.4.0-04
France CTC (UBL credit note) 1.4.0-04
CIUS-RO UBL Invoice 1.0.9 1.0.9
CIUS-RO UBL Credit Note 1.0.9 1.0.9
Rule text from phive-rules 4.6.4.

Check your file

Drop your e-invoice to see whether UBL-DT-26 still fails, and which other rules do.

Updated 6 November 2026