SAP B1 blog

The e-invoicing has moved beyond the theoretical IT project phase. Since January 1st 2025, the mandatory acceptance requirement applies to all domestic companies – without exception. At the same time, new technical standards, stricter cash register regulations, and the European tax initiative ViDA are further increasing requirements. This article summarises the most important developments of the first half of 2026 and places them in context for SMEs and SAP B1 users.

Read more: E-Rechnung 2026: Was sich für KMU und SAP-B1-Anwender jetzt ändert

Transition periods at a glance — who needs to switch and when?

That Growth Opportunities Act The invoicing regulations in § 14 of the VAT Act (UStG) have been fundamentally revised. Since 1 January 2025, VAT law strictly distinguishes between an „e-invoice“ and an „other invoice“. An e-invoice is only issued if the document is in a structured electronic format corresponding to the European standard EN 16931 and enables automated processing. Standard PDFs, scans, or image files therefore do not count as e-invoices.

For invoice dispatch, tiered transitional periods apply according to § 27 para. 38 of the German Value Added Tax Act (UStG):

Period	Who is affected?	What applies to shipping?
01.01.2025 – 31.12.2026	All companies	Paper and PDF (with consent) remain permissible; e-invoicing is voluntarily possible
01.01.2027 – 31.12.2027	Previous year's revenue over 800,000 euros	E-invoicing only (EN 16931) or EDI
01.01.2027 – 31.12.2027	Previous year's revenue up to €800,000	Paper and PDF still permitted
From 01.01.2028	All companies	Electronic invoicing only — without exception

The obligation to receive [invoices] has applied since January 2025 to every domestic entrepreneur – including small businesses, associations with entrepreneurial activities, and legal entities under public law.

Exceptions only exist for small value invoices up to 250 Euros gross (§ 33 UStDV), travel tickets (§ 34 UStDV) and certain tax-exempt transactions according to § 4 numbers 8 to 29 UStG. Important: If a recipient refuses to accept an e-invoice or lacks the necessary technical equipment, the issuer has already fulfilled their obligation by demonstrably attempting to transmit it. There is no entitlement to a paper invoice.

XRechnung 4.0 and ZUGFeRD 2.5 — the new standards

Both e-invoicing standards will undergo significant further development in 2026. The changes will affect both the data model and practical applicability.

XRechnung 4.0: Collective invoices and ViDA preparation

In March 2026, the Coordination Office for IT Standards (KoSIT) announced the XRechnung 4.0 specification. This standard implements the new European standard EN 16931-1:2026 and goes significantly beyond previous bug-fix releases.

The most important innovation: XRechnung 4.0 resolves the rigid assignment of „one order — one delivery — one invoice“. In future, multiple orders, deliveries, and customer references can be combined in a collective invoice (many-to-one billing). This better reflects real supply chains, however, it poses a challenge for automated invoice verification (three-way matching). ERP systems for new challenges. SAP Business One users should therefore check whether their system can correctly process these collective invoices.

Furthermore, the data model includes new fields for bank details, payment terms, early payment discounts, and late payment penalties. These fields prepare for the transaction-related real-time reporting mandated by the European initiative VAT in the Digital Age (ViDA) from 2030. In addition, a new „Extension Component Library“ allows for industry-specific XML extensions. XML attachments will be anchored in the European core model in the future – no longer solely in the national extension.

A preview version of the specification will be available to software developers in the course of 2026. The final release bundle with validation artefacts and syntax mappings (UBL 2.5 and CII D25A) will follow at the end of 2026. In parallel, the PeppolThe network will discontinue all profiles below version 3.0 as of 1 August 2026, making a swift migration unavoidable.

ZUGFeRD 2.5: Two-stage release with industry-specific extensions

The Forum for Electronic Invoicing Germany (FeRD), in consultation with the French partner association FNFE-MPE, published version ZUGFeRD 2.5 (identical to Factur-X 1.09) on 10 June 2026. Due to the high demands of testing and quality assurance, the release will be implemented in two phases:

• Step 1 (published 10 June 2026): Mandatory update of code lists to the current EN 16931 standard and functional extensions in the „EXTENDED“ profile for interoperability with the French B2B e-invoicing mandate.
• Step 2 (announced shortly): Integration of the gross invoicing function — invoices without a detailed breakdown of VAT at line item level. This function addresses specific business scenarios in the book trade, publishing and the oil sector.

XRechnung vs. ZUGFeRD — Differences at a glance

Feature	XRechnung 4.0	ZUGFeRD 2.5
Format type	Pure XML (UBL or CII); requires external viewer	Hybrid: PDF/A-3 with embedded XML
Reference to standards	EN 16931-1:2026 (full integration of the new data model)	EN 16931 (continuous code list maintenance, preparation for revision)
Main functions	Multi-Order Billing, XML Core attachments, decentralised industry extensions	Updated code lists, French B2B contract, gross invoices
Typical Use	Public sector (B2G), and increasingly B2B as well	Domestic and cross-border B2B trade; also suitable for B2C and B2G

For SAP B1 users, this distinction is important: with its hybrid format, ZUGFeRD offers the advantage that recipients can at least view the PDF component without needing any special software. XRechnung, on the other hand, requires a viewer or ERP integration.

Cash management meets e-invoicing — new obligations from 2026

On 1 February 2026, the Second Ordinance Amending the Point-of-Sale Security Ordinance (KassenSichV) came into force. In addition to this, the Federal Ministry of Finance (BMF) comprehensively amended the application circular relating to Section 146a of the German Fiscal Code (AO) in a letter dated 17 March 2026. As a result of this amendment, the tax authorities expressly recognise e-invoices in structured XML format as a permissible form of document within the meaning of Section 146a(2) of the German Fiscal Code (AO).

However, this recognition brings new technical requirements. If a cash register system creates a receipt as an e-invoice (e.g. in ZUGFeRD or XRechnung format), the cryptographic transaction data from the certified technical security device (TSE) must necessarily be included in the XML data stream. Specifically, this affects:

• the process completion check value,
• the continuous signature counter and
• the serial number of the TSE security module.

While this merger of POS till data and e-invoicing structures reduces paper consumption in the long term, it considerably increases the demands on the software architecture of the till systems.

In this context, the Tax Law Committee of the German Tax Advisors Association (DStV) criticised the planned mandatory use of cash registers from 1 January 2027 for businesses with annual sales exceeding €100,000 at its annual meeting on 20 April 2026. The DStV calls for adherence to the „once-only principle“: data already available to the tax authorities should not have to be reported again.

GoBD-compliant archiving — what matters

The Federal Chamber of Tax Advisors (BStBK) published an updated FAQ catalogue on e-invoicing in March 2026, addressing key questions on GoBD-compliant archiving clarifies.

The most important rule: the structured XML data set is considered the legally binding original for tax purposes. This original must be archived immutably. Simply storing a PDF copy or a paper printout of the XML structure is not sufficient, as it leads to a loss of machine readability. The retention period according to § 14b (1) UStG is eight years, but is regularly extended to ten years in the GoBD context and if it remains tax-relevant.

For hybrid formats such as ZUGFeRD, both components — PDF and XML — must be archived in a tamper-proof manner, provided that the PDF component contains additional tax-relevant information (such as account assignment entries or approval notes). Transmission emails are only subject to retention if they themselves contain business or booking-relevant information. If the email merely serves as a transport medium, the archiving obligation does not apply.

Specifically for SAP B1 users, this means that the ERP system must be able to establish an irresolvable connection between the booking and the archived XML data record. The use of a certified document management system (DMS) with unique index keys minimises liability risks.

Validation and protection of trust in audit of accounts

The processing of incoming e-invoices requires two-stage workflows. Technical validation and content plausibility checks are intertwined in this process. The tax authorities distinguish between three error categories:

• Formatting error: The document does not technically qualify as an e-invoice according to § 14 para. 1 sentence 6 of the German VAT Act (UStG) and is considered a different type of invoice.
• Business rules errors: Logical contradictions or missing mandatory fields within the XML data set.
• Content errors: Factually incorrect information despite correct syntax — for example, an incorrect tax rate.

The BMF recommends the use of standardised validation software. At the same time, the tax administration also grants important protection of legitimate expectations: if a company successfully validates an incoming e-invoice using a common tool and applies commercial due diligence, it is entitled to trust its correctness regarding format and business rules and to claim the input tax deduction.

However, the DStV emphasises that a purely technical validation does not replace an assessment of the factual circumstances. Automated syntax checks do not detect incorrect factual statements. Faulty validation reports should be documented and archived. It is best to have deviations corrected directly with the invoice issuer.

Advance payments, final invoices and construction services — special cases in XML format

The BStBK FAQ catalogue provides clear guidelines for complex booking scenarios:

Invoices for advance payments: The XRechnung standard code directory does not have a specific code for down payments. Manually entering such a code will result in system errors. The BStBK and BMF therefore recommend submitting down payment invoices using the standard code 380 („Commercial invoice“). The free text field „Invoice note“ (BT-22) must mandatorily contain the designation „Anzahlungsrechnung“.

Final invoices: The current business terms structure makes it difficult to fully automate the reconciliation of advance payments and final balances in a purely structured final invoice. There are two approaches: either a pure final invoice is created, which only shows the open outstanding balance, or a detailed final invoice attachment is embedded as a PDF into the XML data record. However, the latter limits the degree of automation in accounts payable.

Construction services Until 30 June 2030, a transitional arrangement will apply. In the structured part of the e-invoice, only the sum values per construction service need to be captured in a machine-readable format. The detailed breakdown of services (e.g., according to GAEB standard) may be attached as a human-readable PDF and referenced in the XML file.

For SAP B1 users with down payment or construction processes, it is worthwhile to check whether existing invoice workflows already reflect these requirements.

Europe Unites — ViDA and the Consequences for Small and Medium-sized Enterprises

The German e-invoicing obligation does not stand in isolation. The EU initiative VAT in the Digital Age (ViDA) also mandates a transaction-related real-time reporting obligation for cross-border B2B sales from 1 July 2030. This reporting obligation is based on structured e-invoices and replaces the previous recapitulative statements.

For domestic transactions, EU Member States may introduce their own reporting systems, provided these comply with EN 16931 This leads to significant fragmentation, however:

Country	B2B obligation from	System and formats
Germany	Phased from 2025 (Receipt) / 2027–2028 (Dispatch)	EN 16931 (XRechnung, ZUGFeRD); EDI
France	From September 2026 (receipt all; dispatch large corporations), September 2027 (SMEs)	Portal model (public billing portal + private PDP platforms); UBL, CII, Factur-X
Belgium	01.01.2026 for everyone	Decentralised network, Peppol BIS as standard pathway
Poland	From February 2026 (large enterprises), April 2026 (all others)	Central Clearance System (KSeF); proprietary XML schema FA(3)
Netherlands	Scheduled for 1 January 2030	Peppol Network as a Unified Infrastructure

This diversity has one clear implication: companies with cross-border supply chains must set up their ERP and invoicing systems on a modular basis. Stand-alone solutions that merely meet the minimum German requirements lead to compliance issues and high adaptation costs in international business relationships.

Furthermore, in its statement on the draft Annual Tax Act 2026, the Federal Chamber of Tax Advisers calls for better protection for recipients acting in good faith when claiming input tax deductions from invoices issued by taxable persons who have actually paid tax. As the recipient of the service is often unable to determine from the invoice data alone whether the tax has already been incurred by the issuer, there is a risk of unjustified additional tax claims arising during tax audits in the absence of statutory safeguards.

What SMEs and SAP B1 users should do now

The developments of the first half of 2026 clearly show: tax compliance and digital business processes are inextricably merging. Three areas of action deserve immediate attention:

Building end-to-end digital workflows: An email inbox for receiving XML files will not suffice in the long term. Companies require interfaces that enable seamless validation, automated accounting, and audit-proof archiving. SAP B1 offers integration possibilities with DMS systems and validation tools for this purpose – these should be evaluated and set up now.

Check and adjust exceptional cases: Who with Advance invoices, When working with final invoices or construction services, one should review their own processes against the BStBK FAQ guidelines. The technical framework conditions of the XML data fields, in many cases, necessitate adjustments in the invoicing workflow.

Ensure modularity and European scalability: When selecting and updating ERP systems, it's not just about support for XInvoice and ZUGFeRD. Standardised APIs for connecting to foreign clearance systems will become indispensable at the latest with the ViDA mandate from 2030. Those who invest in flexible, updatable processes today will reduce tax risks during tax audits and simultaneously lay the foundation for automated finance and accounting processes in the European single market.