Global E-Invoicing Compliance Update: September 2026

Global E-Invoicing Mandates: Key Regulatory Updates and Upcoming Deadlines for September 2026

If you work in indirect tax, September probably felt like a month of milestones. France went live, Poland's KSeF is bedding in, Slovakia is counting down to January. But when I went through the regulatory updates our team tracked during the month, the story that stood out was how many different stages businesses are now managing at the same time.

For a multinational, global e-invoicing is now a portfolio of programmes running in parallel, rather than just a list of e-invoicing mandates you deal with one by one. Some regimes you've just switched on, others land in the next few months, and some are still being designed, but they'll shape your systems for years.

E-Invoicing Go-live is Not the Finish Line

In France on 1 September, large and medium-sized businesses began issuing e-invoices, and every business now has to be able to receive them. Almost immediately, the government confirmed that no penalties would apply for e-invoicing or e-reporting non-compliance for the rest of 2026. That's welcome breathing space, but it isn't an exemption. The obligation is live. The authorities are simply giving companies time to settle in.

Poland tells a similar story. On 16 September, the Ministry of Finance announced that penalties for KSeF errors will stay suspended until the end of 2027. Meanwhile, KSeF becomes mandatory for all taxpayers from 1 January 2027. Token-based authentication had been due to end in December, but it's now expected to stay available. That still depends on an amended regulation, though. If your integration relies on tokens, this is exactly the kind of detail that changes your project plan.

In Greece on 30 September, the authorities moved mandatory e-invoicing for second-wave businesses (gross revenue up to €1 million) from 1 October to 2 November 2026. They also moved Phase B of digital inventory movement reporting to 1 January 2027. That second change matters because it takes compliance beyond the invoice and into how goods are loaded, moved, received and tracked.

The lesson is that go-live doesn't stop the rules from moving. Grace periods, authentication changes and revised timelines keep arriving after the date you circled in your plan.

Upcoming E-Invoicing Mandates and Deadlines

While teams stabilise live regimes, the next deadlines are close. Look at 1 January 2027 alone:

• KSeF becomes mandatory for all Polish taxpayers
• Slovakia's eFaktúra mandate begins
• Croatia extends e-invoicing to taxpayers who aren't VAT-registered
• San Marino's domestic B2B mandate takes effect
• Greece's Phase B inventory reporting starts

Slovakia shows how practical the final months get. September's guidance covered whether accounting systems are ready, how to choose a certified delivery provider (known locally as a "Digital Postman") and how to map VAT category codes. By late September, more than 12,000 entities had chosen a provider, showing how quickly implementation is moving from policy into practice. This is where e-invoicing implementation really happens: in system readiness and data mapping, not in the headline mandate.

The Philippines issued guidance ahead of its 31 December 2026 deadline. It made clear that issuing e-invoices and reporting sales data electronically are separate obligations, and the reporting rules are still to come.

Spain shared more detail on its future B2B model and public solution. However, key pieces, including the Ministerial Order and the test environment, were still pending at the time. Since then, Spain has published Order HAC/1028/2026, which formally starts the implementation timeline for B2B e-invoicing.

Global E-Invoicing: The Road Ahead

Even with resources stretched by near-term deadlines, September also brought clearer long-term roadmaps.

Bulgaria published a draft law proposing mandatory structured e-invoicing, real-time reporting and pre-filled VAT returns from 1 January 2028.

Germany said a voluntary pilot of its B2B digital reporting system should start in early 2029, with go-live planned for 1 July 2030.

The Netherlands announced plans to introduce mandatory domestic B2B e-invoicing from 1 July 2030, with domestic digital reporting following in July 2031.

These dates may feel distant. But the decisions you make today about ERP upgrades, data models and providers will decide whether those programmes go smoothly or force you to rebuild.

What E-Invoicing Updates Mean for Tax and IT Leaders

Put it together and your team may be doing three jobs at once. You're stabilising regimes that just went live, implementing the ones due in months, and making system decisions for requirements years away. If you run these as separate country projects, you'll likely pay twice: once to comply, and again to fix the patchwork.

The businesses that cope best treat e-invoicing as an ongoing discipline, not a project with an end date. In practice, that means:

• One clean tax data foundation that supports both tax calculation and tax compliance in every country
• Continuous regulatory monitoring that picks up the detail after the announcement, not just the headline
• Systems flexible enough to take on the next country, rule change or grace period without starting over

At Vertex, our regulatory team tracks and validates changes like these across jurisdictions worldwide every month, and we build that knowledge into how our customers calculate tax and stay compliant. September reminded us why that matters. The mandate tells you when to act. The guidance, specifications and revisions that follow tell you what implementation actually requires.

Can your approach absorb the next update? Let’s chat Vertex e-invoicing and tax compliance solutions.