# BR-DE-26 Corrected invoice must reference at least one preceding invoice

Under German XRechnung rule BR-DE-26, when an invoice is issued with InvoiceTypeCode 384 (Corrected invoice / Korrigierte Rechnung), it must include at least one preceding invoice reference group (BG-3 / PRECEDING INVOICE REFERENCE) specifying the previous invoice identifier in BT-25 (PrecedingInvoiceReference). In German accounting and tax law (§ 14c UStG / GoBD), a corrective billing document cannot stand alone without an explicit reference linking it to the original commercial invoice being adjusted or corrected.

## Problem Description

Under German XRechnung rule BR-DE-26, when an invoice is issued with InvoiceTypeCode 384 (Corrected invoice / Korrigierte Rechnung), it must include at least one preceding invoice reference group (BG-3 / PRECEDING INVOICE REFERENCE) specifying the previous invoice identifier in BT-25 (PrecedingInvoiceReference). In German accounting and tax law (§ 14c UStG / GoBD), a corrective billing document cannot stand alone without an explicit reference linking it to the original commercial invoice being adjusted or corrected.

> **ERROR**: XRechnung 3.0

## Context and Significance

An invoice with InvoiceTypeCode 384 without a preceding invoice reference violates German XRechnung rule BR-DE-26 and fails KoSIT validation.

## Solution

In your ERP billing module, when generating a corrected invoice (type 384), populate the preceding invoice reference with the original invoice number (BT-25) and optionally the issue date (BT-26). In UBL 2.1 syntax, populate <cac:BillingReference><cac:InvoiceDocumentReference><cbc:ID>INV-2025-001</cbc:ID><cbc:IssueDate>2025-12-15</cbc:IssueDate></cac:InvoiceDocumentReference></cac:BillingReference>. In UN/CEFACT CII syntax, populate <ram:InvoiceReferencedDocument><ram:IssuerAssignedID>INV-2025-001</ram:IssuerAssignedID><ram:FormattedIssueDateTime>...</ram:FormattedIssueDateTime></ram:InvoiceReferencedDocument> under <ram:ApplicableHeaderTradeSettlement>. If the document is a standard commercial invoice, set InvoiceTypeCode to 380 (Commercial invoice) instead.

- validate
- convert

## Valid Examples

- Corrected invoice (type 384) referencing preceding invoice "INV-2025-001" (BT-25)
- Corrected invoice referencing preceding invoice with issue date 2025-11-30 (BT-26)

## Invalid Examples

- Invoice with cbc:InvoiceTypeCode = 384 completely omits cac:BillingReference
- Corrected invoice declares cac:BillingReference without cbc:ID in InvoiceDocumentReference

## Code Examples

### Valid XML
```
<cbc:InvoiceTypeCode>384</cbc:InvoiceTypeCode>
<cac:BillingReference>
  <cac:InvoiceDocumentReference>
    <cbc:ID>INV-2025-001</cbc:ID>
    <cbc:IssueDate>2025-12-15</cbc:IssueDate>
  </cac:InvoiceDocumentReference>
</cac:BillingReference>
```

### Invalid XML
```
<cbc:InvoiceTypeCode>384</cbc:InvoiceTypeCode>
<!-- Missing cac:BillingReference (BG-3 / BT-25) for corrected invoice type 384 -->
```

## Affected Fields

- [BT-25 Preceding invoice reference](/resources/xrechnung/bt-25-preceding-invoice-reference)
- [BG-3 Preceding invoice reference](/resources/xrechnung)
- [BT-3 Invoice type code](/resources/xrechnung/bt-3-invoice-type-code)
- [BT-26 Preceding invoice issue date](/resources/xrechnung/bt-26-preceding-invoice-issue-date)

## Related Rules

- [BR-DE-17](/resources/kosit-validator-errors/br-de-17-invoice-type-code-should-be-xrechnung-supported)
- [BR-25](/resources/kosit-validator-errors/br-25-invoice-line-item-name-must-be-present)

## Validation Tools

- [Official KoSIT Validator](https://erechnungsvalidator.service-bw.de/): Validate your XRechnung files against all BR-DE rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Automatic validation error fixes when converting.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [Complete Error List](/resources/kosit-validator-errors): Overview of all German XRechnung validation rules.