SAP B1 blog

From 1 January 2025, a mandatory requirement for the receipt of structured electronic invoices will apply to all domestic B2B companies in Germany. No deferral, no transition period for receipt – those who are not yet ready to receive today will no longer be acting in accordance with the law. For medium-sized companies, this means that e-invoicing is not a project for tomorrow. It is already a legal obligation.

Read more: E-Rechnung im Mittelstand: Die Uhr läuft

What the Growth Opportunities Act specifically demands

That Growth Opportunities Act 2024 defines a mandatory three-stage plan for e-invoicing obligations in the German B2B sector. None of the three phases is optional:

• Phase 1 – 01.01.2025: All companies must be able to receive and process e-invoices. This phase is already underway.
• Phase 2 – 01/01/2027: Small and medium-sized enterprises with an annual turnover below €800,000 must use structured invoices in the format XInvoice or ZUGFeRD dispatch.
• Phase 3 – 01.01.2028: Complete B2B e-invoicing mandate for all remaining businesses in Germany – without exception.

The European mandate also lies behind it ViDA (VAT in the Digital Age), which will gradually introduce a real-time reporting obligation for VAT data in cross-border transactions from 2028. Consequently, companies that have not yet laid the groundwork will also come under pressure at the European level.

A PDF via email is not an e-invoice

Herein lies the most common misunderstanding in the Mittelstand: a scanned or digitally created PDF invoice sent via email does not meet the legal requirements of the Growth Opportunities Act. Legally recognised e-invoices are machine-readable, structured datasets, that can be processed without manual intervention and comply with the European standard EN 16931.

In practice, three formats have become established that meet this standard:

• XInvoice – XML-based, mandatory for invoices to government bodies (B2G), also permissible in B2B.
• ZUGFeRD – a hybrid format of PDF/A-3 and embedded XML, particularly suited for domestic B2B traffic.
• Peppol BIS Billing – XML-based via the Peppol network, relevant for cross-border transactions.

What risks actually arise from non-compliance

Many managing directors consider the E-invoicing obligation as an IT topic with manageable urgency. In reality, however, the consequences of a delay are already measurable.

Penalties and fines will be levied against companies that are not ready to receive invoices – from 1 January 2025. Furthermore, large clients are increasingly excluding suppliers from their supply chains if they are not digitally accessible. Those without a Peppol ID or unable to receive structured invoices are effectively unreachable for digitally established business partners.

In addition, there is the tax risk: GoBDCompliance-compliant archiving is mandatory. Those who merely save ZUGFeRD documents as PDFs lose the embedded XML – and thus violate the principles of proper accounting. This can lead to back payments during a tax audit.

No one-size-fits-all recipe: Why configuration differs for each company

This is the point that is systematically underestimated in public discussions about e-invoicing: there is no universal configuration, that suits all medium-sized companies. The specific implementation effort – and therefore also the time required – depends on a number of company-specific factors that can only be determined through a careful inventory.

SAP version and EDS status: Not installed does not mean inactive

The Electronic Document Service (EDS) in SAP Business One is the technical foundation for legally compliant e-invoice transmission and receipt. It is available from version 10.0 FP 2405 – however, installed is not the same as configured, and configured is not the same as in productive dispatch operation. Companies running SAP B1 on older versions must first plan an upgrade before the EDS setup can even begin. This means lead time and resource requirements that are not factored into any statutory deadlines.

Crystal Reports, Coresuite, or standard EDS?

A further key difference lies in the layout system used. Crystal Reports is the standard tool for invoice layouts in many SAP B1 installations. However, this comes with an important technical restriction: Crystal Reports cannot natively generate PDF/A-3, and therefore not a valid ZUGFeRD document. Consequently, a two-part process is necessary: Crystal Reports provides the visual PDF layer, the EDS then injects the XML and creates the finished ZUGFeRD document from it.

Companies using the Coresuite Layout Designer in version 8.30 or higher, however, can natively generate PDF/A-3 without this two-part process. Which path a company takes therefore depends directly on the installed add-on stack. Those who don't yet have an idea which variant is relevant for their system can quickly fall into a time trap during project planning.

Peppol connectivity: Additional infrastructure required

For companies that want or need to use Peppol – whether for international partners or because clients already require it – another variant is added. Peppol AS4 shipping via SAP B1 requires the SAP BTP Peppol Exchange Service, which must be licensed and configured separately. Anyone who doesn't already use this faces a standalone sub-project that goes far beyond simple EDS activation.

Multiple formats in parallel: automatic rather than manual

Many small and medium-sized enterprises (SMEs) simultaneously have customers in the domestic B2B sector, with public authorities, and in international business. In practice, this means: ZUGFeRD for German B2B traffic, XRechnung with Leitweg-ID for public sector clients, Peppol BIS for international recipients – and all of this in parallel. SAP B1 can automate this choice of format on a per-customer basis, but this requires the master data to be fully maintained. If the Leitweg-ID is missing for a public authority customer or the Peppol-ID for an international partner, automation fails precisely where it is needed most.

Silent Errors: The Underestimated Risk

A particularly insidious configuration problem that frequently occurs in practice is: if the EDS is incorrectly configured, SAP Business One may send out technically invalid invoices - without an error message appearing in the frontend. The posting process goes through, the invoice lands with the recipient, and is rejected there. Only a complete end-to-end test with KoSIT-Schematron validation actually provides certainty. Anyone who has not yet carried out this test simply does not know whether their outgoing invoices are valid.

What that means for planning

All these variables make one thing clear: before any implementation, a structured inventory must be taken. Which SAP B1 version is running? Is the EDS licensed and configured? Which layout tools are in use? Which formats are required on the output and input sides? Are master data complete? Is the Peppol infrastructure in place? The answers to these questions will determine whether a project can be completed in a few weeks or whether an upgrade, licensing, or more extensive master data cleanup must be carried out first.

This is precisely why it's counterproductive to wait until just before the next deadline to analyse. Those who know the status quo now can plan realistically. Those who wait are planning blind.

Peppol: The way everyone will go

Anyone who consistently follows the development of recent years to its logical conclusion comes to a clear conclusion: sending invoices by email is a dying model. Not as an opinion, but as a foreseeable regulatory reality.

What Peppol is – and what it isn't

Peppol is not a file format. It is a transport network: a global infrastructure that defines how structured business documents are transferred securely, encrypted and legally compliant from one company to another – regardless of which ERP system the sender or recipient uses. Therefore, while XRechnung or ZUGFeRD specify what is included in an invoice, Peppol specifies how this data is transported: with a digital signature, end-to-end encrypted, and with a legally compliant confirmation of receipt.

The principle is designed so that a company can change its access point without losing its reachability on the network. Expensive, proprietary EDI point-to-point connections are thus replaced by a scalable principle: connect once, reach everyone.

Global mandates create facts – already today

In 2026, Peppol will no longer be a niche European topic. With over 80 connected countries and the PINT (Peppol International) standard as a global interoperability framework, Peppol is evolving into the de facto standard for international e-invoicing exchange. Specific country mandates are already creating pressure to act:

• Belgium Peppol has been mandated as a mandatory standard for all B2B transactions since 01/01/2026.
• Poland operates an active clearance system with KSeF, which will be obligatory for large and medium-sized enterprises from Spring 2026 – with real-time tax validation for every transaction.
• Spain followed by its own mandate from July 2026 for large companies, SMEs from 2027.
• VAE From July 2026, Peppol will roll out PINT as the first 5-corner model outside the EU.
• Great Britain aims for a B2B mandate for April 2029, the consultation phase is already underway.

For German companies with suppliers or customers in these countries, Peppol is therefore no longer a future option – but a current requirement.

ViDA: Peppol to become EU infrastructure

The European reform project ViDA is reaching its next milestone. From 2028, there will be a real-time reporting obligation for VAT data for cross-border intra-community transactions. The EU Council's position has confirmed the so-called 5-Corner Model as the standard for this rollout: a fifth instance – the tax authority – will receive real-time access to the transaction data, either before or during the delivery of the invoice. In countries that adopt this model, an invoice without clearance by Corner 5 will not be legally valid.

This means: Peppol is not just the way for structured document exchange in the B2B sector. It is the technical basis on which ViDA is built. Those who want to be compliant by 2028 will not build the Peppol infrastructure in 2027.

The post-email era has begun

Legally, email remains a possible transport route for structured e-invoices for the time being, but the EU's direction of travel – ViDA, Continuous Transaction Controls, and Peppol/platform models – make a phased transition to network and API-based transmission a de facto inevitability.

Anyone still relying exclusively on email for their transmissions today, while operating within legal parameters, is building on a foundation that is set to be superseded. Server-to-server communication via Peppol AS4 or national clearance APIs is faster, more secure, and offers greater potential for automation. Invoices arriving via Peppol are already technically validated before they reach the ERP system. This creates the prerequisite for largely automated incoming processing and, in a subsequent step, for AI-driven processes such as predictive accounting mapping, anomaly detection, and fraud detection.

For medium-sized businesses, this means: investing in Peppol-enabled infrastructure is not an additional expense for a special case. It is the establishment of the foundation upon which all further compliance requirements of the coming years will be built.

E-invoicing is not an IT upgrade with an optional start date.

It is a legal obligation with three binding deadlines – the first of which has already passed. Configuration realities vary significantly depending on the installed base, and the path towards the Peppol network is regulatorily predetermined. Medium-sized companies that act now gain time for an orderly implementation, avoid fines and supply chain risks, and at the same time lay the foundation for a future-proof, automation-capable finance organisation. Those who wait will pay – sooner or later.