XRechnung 4.0 preliminary version: what software vendors should prepare for EN 16931-1:2026

Bremen, 2 October 2026. Germany’s Coordination Office for IT Standards (KoSIT) published the preliminary version of XRechnung 4.0 through XStandards Einkauf on 15 September 2026. The specification is based on the revised European standard EN 16931-1:2026 and extends the data model with more than fifty business terms and seven business groups. The preliminary version is explicitly not intended for productive use. For every software vendor whose customers invoice German buyers or receive invoices from them, it is nevertheless the moment to fix the roadmap towards the final XRechnung 4.0.

What the XRechnung 4.0 preliminary version contains

The document XRechnung 4.0.0, Vorversion of 15 September 2026 describes the German CIUS and extension on top of EN 16931-1:2026. According to XStandards Einkauf it adds more than fifty new business terms and seven new business groups. Six extensions stand out:

• multiple orders and deliveries in a single invoice;
• more detailed delivery information;
• fields for early payment discount (Skonto);
• fields for late payment interest (Verzugszinsen);
• amounts collected on behalf of third parties (Fremdforderungen);
• XML attachments to the invoice.

The specification identifier of the preliminary version is urn:cen.eu:en16931:2026#compliant#urn:xeinkauf.de:kosit:xrechnung_4.0. The identifier for the XRechnung extension is still marked TBD (to be determined) in the document. According to the XStandards Einkauf version overview, the final XRechnung 4.0 is expected in spring 2027, published as a bundle with the technical components. That bundle depends on work at European level: the syntax binding documents and the CEN validation artefacts were not yet available at the time of publication.

Transition: XRechnung 3.0 remains in force

No normative XRechnung release was published in summer 2026. XRechnung 3.0, with 3.0.2 as the current bugfix version, therefore remains in force until at least 31 July 2027. For the underlying standard, parallel use of the existing and the revised version of EN 16931-1 is foreseen until March 2029. According to XStandards Einkauf, the exact transition periods for XRechnung itself will only be announced with the publication of the XRechnung 4.0 bundle.

EN 16931-1:2026 has been ratified and has been available in English since March 2026. The German translation by DIN was announced for 30 September 2026 at the latest. For background on the standard itself, see the knowledge base: What is the EN 16931?

Context: Germany e-invoicing 2027 and Peppol

Since 1 January 2025, every business in Germany must be able to receive e-invoices for domestic B2B transactions. Transition rules apply to issuing: until 31 December 2026 all businesses may still send other invoices, and businesses with a prior-year turnover of no more than EUR 800,000 may do so until 31 December 2027 (FAQ of the Federal Ministry of Finance). The issuing obligation from 1 January 2027 therefore starts on XRechnung 3.0 and ZUGFeRD; the ministry names XRechnung and ZUGFeRD from version 2.0.1 (excluding the MINIMUM and BASIC-WL profiles) as formats that meet the requirements. For more on the mandate, see German e-invoicing mandate 2025: XRechnung, ZUGFeRD and what exporters need to arrange.

KoSIT is also the national Peppol Authority for Germany, and the federal administration has been reachable for XRechnung via Peppol since 2019. In the Peppol BIS Billing 3.0 release notes (release 3.0.21 of May 2026), OpenPeppol has not yet announced a version based on EN 16931-1:2026. Vendors that also support Peppol BIS Billing, ZUGFeRD or Factur-X should track those releases separately, as with the ZUGFeRD and Factur-X update with new versions from 1 September.

What it means and what to do now

For software vendors, the preliminary version is a planning document, not a production change. This checklist helps to organise the transition:

1. Plan the roadmap. Include the final bundle (expected spring 2027), the minimum validity of XRechnung 3.0 until 31 July 2027 and the parallel window for EN 16931-1 until March 2029 in your release planning. Leave room for the official transition periods that will come with the bundle.
2. Extend the data model and mapping. For each new business term, check whether your application holds the data. Multiple orders and deliveries per invoice often require a one-to-many relation that many invoicing modules lack. Early payment discount, late payment interest, third-party amounts and XML attachments require new fields in master data and document structure.
3. Support 3.0 and 4.0 side by side. Build version detection on receipt based on the specification identifier: urn:cen.eu:en16931:2017#compliant#urn:xeinkauf.de:kosit:xrechnung_3.0 versus urn:cen.eu:en16931:2026#compliant#urn:xeinkauf.de:kosit:xrechnung_4.0. Route each message to the right mapping and validation. Keep sending 3.0 by default while it is valid and as long as your customer or the recipient cannot yet handle 4.0.
4. Update validation. Keep the KoSIT validator with the XRechnung 3.0 configuration active and schedule the new configuration and schematron rules as soon as the 4.0 bundle is published.
5. Test with the preliminary version, not in production. Use it for design, test cases and a test environment. Do not send productive invoices with the 4.0 identifier until the final version is available.
6. Inform your customers. Explain what changes, which master data they will need to capture and when your release follows, so the new fields do not come as a surprise.
7. No need to panic. XRechnung 3.0 keeps working. The issuing obligation of 1 January 2027 does not require XRechnung 4.0.

A note for integrators

Integrators that translate XRechnung between ERP, access point and recipient will be running two mapping sets in parallel. Fields that only exist in 4.0 have no counterpart in 3.0. Record per chain which version the sender delivers and which the recipient accepts, and test conversions for loss of information before taking them into production.

Vendors that have mapping, validation and version detection in place before spring 2027 can adopt the final XRechnung 4.0 as soon as KoSIT publishes the bundle, without disrupting ongoing processing on XRechnung 3.0.

Sources

1. KoSIT / XStandards Einkauf: XRechnung 4.0.0, Vorversion, 15 September 2026 (pdf)
2. XStandards Einkauf: XRechnung, Versionen und Bundles
3. XStandards Einkauf: EN 16931, aktueller Stand und Ausblick auf die Einführung der XRechnung 4.0 (1 September 2026)
4. XStandards Einkauf: Standard XRechnung
5. XStandards Einkauf: Peppol in Deutschland
6. Federal Ministry of Finance (BMF): Fragen und Antworten zur Einführung der obligatorischen E-Rechnung
7. OpenPeppol: Peppol BIS Billing 3.0, release notes
8. cosinex: XRechnung 4.0 Vorabversion and EN 16931 (16 September 2026, secondary source)
9. invoice-portal.de: XRechnung 4.0 preview and EN 16931:2026 (secondary source)

Do you build or maintain software that has to process XRechnung 4.0, and are you looking for a Peppol Service Provider or e-invoicing solution that fits your architecture? Compare providers by formats, countries and integration options in the Peppol.now comparison tool.