XRechnung has been the German standard for electronic invoices since 2017 and has been mandatory for suppliers in the public sector since then. With XRechnung 4.0, the implementation of the revised European standard EN 16931-1:2026 is now due: The underlying data model is growing significantly, with partly noticeable effects on existing invoicing processes.

What is XRechnung 4.0?

The EU is setting standards with its regulation EN 16931 a Europe-wide basic framework for electronic invoicing, and XRechnung is the German, very concrete implementation of this set of rules. If the European standard changes, the German implementation must also follow suit, which is exactly what is happening now with version 4.0.

XRechnung 4.0 is the German implementation of the new European standard EN 16931-1:2026, known as CIUS (Core Invoice Usage Specification). A CIUS is a nationally adapted, restricted version of the basic European standard. Since the decision by the IT Planning Council on 22 June 2017, the standard has been continuously developed by the Co-ordinating Body for IT Standards (KoSIT). Version 4.0 builds on this established standard but, unlike previous updates, fundamentally changes the data model.

XRechnung 4.0: the timetable

There isn't a single deadline, but rather several stages that build on each other. First, the European standard will be finally adopted, followed by an initial, not yet usable test version of XRechnung 4.0, and only then will the complete, productive version be released. The current version 3.0 will continue to run in parallel.

The European standard EN 16931-1:2026 was adopted by CEN (European Committee for Standardisation) in March 2026, and the English version became available shortly afterwards. The national announcement is scheduled for 30 June 2026, and the German version is due to be published by 30 September 2026 at the latest. The previous version of the standard, dated 2017, will be withdrawn on 31 March 2029.

A preview version of XRechnung 4.0 itself has been announced for summer 2026. This contains only the text of the specification and is not yet intended for production use. Its purpose is to provide an early overview of the new features. The complete, usable version will only follow once the syntax bindings for UBL and CII, as well as the associated CEN Schematron, are available. There is currently no fixed date for this, as this work is being carried out by the European Committee for Standardisation (CEN). An initial official version of the new UBL 2.5 syntax, known as the Committee Specification, has been available since April 2026. The public review period runs until 28 July, after which it will be published as an official OASIS standard within three to four weeks.

Independently, an updated version of the current XRechnung 3.0 will be released in Summer 2026, which will include an update to the associated CEN schematron.

Will XRechnung 3.0 still be valid after the changeover?

The current version won’t just disappear overnight. It will continue to work, but from a certain point onwards it will no longer receive any new features.

XRechnung 3.0 will remain in force even after the release of version 4.0. The old According to KoSIT, EN 16931-1 and standards derived from it may be used until March 2029. However, XRechnung 3.0 will only continue to operate in minimal mode after that: updates to the 2017 CEN Schematron will continue to be released, but there will be no further functional developments. According to KoSIT, anyone in any doubt should upgrade directly to XRechnung 4.0.

For companies switching to XRechnung for the first time, this leads to a clear recommendation: the cost of the transition should only be incurred once for new user groups. Anyone who is already switching to the EN 16931-1 standard for the first time should therefore aim to adopt version 4.0 directly, if possible, rather than investing in version 3.0 first.

The most significant changes to the content

In future, an invoice will contain significantly more individual data fields than before, and some of the information that currently appears as free text on the invoice will become a fixed, machine-readable field.

The standard’s data model expands significantly in the 2026 edition: the number of numbered main terms (Business Terms) rises from 164 to 216, an increase of 52 fields or 32 per cent – the largest since the standard was introduced. The number of structural business groups has increased from 32 to 39, whilst the number of auxiliary attributes has risen moderately from 19 to 22.

Collective invoices: the end of the rigid 1:1:1 rule

Until now, each invoice had to correspond exactly to one order and one delivery. This is set to change; in future, an invoice will be able to cover several orders and deliveries, for example as a collective invoice at the end of the month.

One of the most significant practical changes concerns the previous basic principle of "one order, one delivery, one invoice". This strict linkage is being removed: in future, it will be possible to combine several orders, deliveries and customer references into a single invoice. This corresponds much better to real-world supply chain scenarios, but also requires an adjustment to the three-way reconciliation (order, delivery, invoice) in companies’ approval processes.

Structured payment terms: cash discount and interest on late payments

At present, ‘cash discount’ usually appears only as a phrase within the body of an invoice; in future, it will have its own dedicated field, much like a telephone number is now entered into a separate form field rather than appearing within the running text.

This will enable cash discounts, interest on arrears and the account debited to be recorded in a structured manner in future. This makes this data machine-readable, which represents a tangible efficiency gain, particularly for the automated posting of cash discounts in the accounts.

Mandatory information: Delivery and performance date

With only a few exceptions, the delivery or service date will become mandatory. Exceptions include, in particular, pro forma invoices and invoices for advance payments. Companies that have not consistently filled in this field to date should adapt their invoicing processes accordingly.

Further minor changes

The Buyer Reference (BT-10, usually the routing ID in Germany) remains a mandatory field. Although the standard generally permits multiple uses of this field, the German implementation continues to require that only one routing ID be used. For the Invoice Type Codes (BT-3), the previous recommendation has been removed and the associated warning message deactivated, which in practice reduces some of the friction caused by existing validations.

In future, invoice lines will be able to include more references, such as to orders, delivery notes, goods receipts, dispatch notes and previous invoices, as well as specific delivery details for each line, such as the consignee, delivery location, delivery date and delivery address. Tax and reporting data will also be more precise: grounds for exemption, non-VAT types and goods and services codes can now be mapped in greater detail.

Two functions are being moved from the extension area to the core

Two functions that were previously only available via the so-called XRechnung extension are now also possible in the core model following this update: XML documents as attachments and the mapping of through-items (third-party payments). As a result, the XRechnung extension itself will initially be scaled back, although sub-items at invoice line level (sub-invoice lines) will be retained. In addition, an assessment is currently underway to determine whether further functionalities should be added, taking into account so-called Common Extension Components, for example for gross-price invoices.

New opportunities for industry expansion

The management of extensions is being fundamentally revised. With a new "Extension Component Library," industries will be able to develop and publish their own sector-specific extensions in the future, for example, for construction or healthcare, without having to wait for adjustments to the core standard. Responsibility for these extensions will lie with the respective industries themselves.

Relation to ViDA

The revised data model also takes into account the requirements of the European ViDA-Initiative (VAT in the Digital Age) and its digital reporting obligations. Specifically, KoSIT refers here to more detailed bank account details, several parallel payment terms and additional buyer identifiers, which may become relevant for subsequent real-time reporting.

New syntax: UBL 2.5 and CII D25A

XRechnung 4.0 is based on the new syntax versions UBL 2.5 and UN/CEFACT CII D25A. This has a practical consequence: invoices that were valid under version 3.0 will no longer automatically pass validation under 4.0. A mere version change on the software side is therefore not sufficient; the validation logic must also be adapted.

Outstanding issues

Not every detail has yet been finalised. Several applications relating to the underlying UNTDID code lists are still pending; a decision on these is expected in November 2026. Among other things, this affects the Invoice Type Codes for cancellation, partial and final invoices, the Scheme Identifier for the Buyer Reference, the mapping of a deduction from the customer’s account, and regulations concerning online customer mailboxes, for example in the banking sector.

There is also currently a delay in the technical validation process: the relevant work has been put on hold because there are still unresolved issues regarding copyright. It is hoped that clarification regarding further use ("derivative use") will be provided shortly, but this has not yet been forthcoming.

XRechnung 4.0 and Peppol

XRechnung 4.0 is being discussed alongside Peppol BIS Billing 4.0, as both are based on the same EN 16931-1:2026 standard. Currently, Peppol BIS Billing 3.0 is considered functionally equivalent to XRechnung 3.0 thanks to the German DE-NRS regulatory framework. In future, Peppol BIS 4.0 is intended to combine BIS 3.0 and the international PINT profile on a common basis.

What does this mean for ZUGFeRD?

ZUGFeRD will also be adapted to EN 16931-1:2026. However, further development depends on when the CII-D25A schemas are officially published, and a separate, independent timetable for ZUGFeRD is not currently available.

What companies should prepare for now

Important note beforehand: There is no single cut-off date from which XRechnung 4.0 becomes mandatory. The actual B2B invoicing obligation remains initially independent of this. The obligation to, Receive e-invoices to be able, has been in effect for all companies since 1 January 2025. When Shipping The obligation applies in stages: for companies with an annual turnover of over 800,000 Euros from 1 January 2027, and for all other companies from 1 January 2028.

Nevertheless, early preparation is worthwhile. It makes sense to review your own invoicing process with the new collective invoicing model in mind. Exchanging views with an e-invoicing provider such as SGH on the question of Industry 4.0 readiness is also an obvious next step.

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