warningPeppol BIS 3.0

IN-CUSTOMIZATION-FORMAT:CustomizationID format recommendation

CustomizationID should follow Peppol BIS Billing 3.0 format

Severity
Warning
Rule set
Peppol BIS 3.0
Country
All EU
Fix type
AUTO-FIX

Engine Classification

Structural normalization · No financial impact · Safe deterministic remediation

What is IN-CUSTOMIZATION-FORMAT?

IN-CUSTOMIZATION-FORMAT is a warning validation rule defined in the Peppol BIS 3.0 specification. It validates the CustomizationID element in the UBL invoice XML.

This is a soft validation failure. The invoice may pass initial transmission, but non-compliant values in this field can cause problems during tax audits, buyer-side processing, or downstream VAT reconciliation.

Target path: /Invoice/cbc:CustomizationID

Get API AccessTest This Error ↓

Why This Error Matters

CustomizationID determines which validation rules apply to the invoice.

IN-CUSTOMIZATION-FORMAT is a soft failure. The invoice may pass initial validation, but the non-compliant field can cause issues at the receiving end — tax authorities may flag it during audits, buyer ERP systems may fail to process it, or VAT reconciliation may produce mismatches. Fixing warnings before they accumulate prevents larger compliance gaps.

Invoice Navigator can automatically correct this error in your pipeline. The fix is applied with full audit evidence, so your compliance trail remains intact.

Validator Behavior

  • ·Generates validation warning
  • ·Rejected by PEPPOL Access Points
  • ·Error returned: IN-CUSTOMIZATION-FORMAT
  • ·Specification: Peppol BIS 3.0

How to Fix It

1.

Set CustomizationID

urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0

2.

For credit notes

Same identifier applies

3.

Country extensions

May need additional extension for country-specific rules

Before / After

Failing XML
<Invoice>
  <cbc:CustomizationID><!-- invalid or missing value --></cbc:CustomizationID>
</Invoice>
Corrected XML
<Invoice>
  <cbc:CustomizationID>correct-value</cbc:CustomizationID>
</Invoice>

Technical Reference

XPath/Invoice/cbc:CustomizationID
SpecPeppol BIS 3.0
Operationset_value

Code Example

<cbc:CustomizationID>urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0</cbc:CustomizationID>

Common Causes

  • ·Wrong specification ID
  • ·Using EN16931 only
  • ·Outdated Peppol version

Seeing this in production? The API handles IN-CUSTOMIZATION-FORMAT automatically. See the fix response →

Commonly Seen In

All Peppol invoicing software

Frequently Asked Questions

The CustomizationID must match the Peppol BIS 3.0 specification identifier.

Use the correct Peppol BIS 3.0 CustomizationID. Invoice Navigator can help identify and fix this issue.

Yes, PEPPOL-EN16931-R002 is a critical error that must be fixed.

See Also

Peppol Validator

Check your invoice now

Related Errors

PEPPOL-EN16931-R001

Business process identifier required

Last updated: 27 February 2026

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Handle IN-CUSTOMIZATION-FORMAT Automatically in Your Pipeline

The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.

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