EN 16931 vs Peppol BIS 3.0.21: What Changes in 2026?

Short version: these are two separate things moving at different speeds, not one single update. EN 16931 (the European semantic data model for e-invoices, meaning the rulebook for what an invoice must contain, not how it technically travels) got a new edition, EN 16931-1:2026, approved by CEN on 13 March 2026 and made available on 18 March 2026. At the same time, Peppol BIS Billing, Peppol’s business-document implementation specification and the layer that makes that same standard actually work inside the Peppol network, gets a new version 3.0.21, which becomes mandatory from 17 August 2026. These two dates don’t cover the same ground: Peppol BIS 3.0.21 is not a migration to the new EN 16931-1:2026 standard, because that version still runs on the 2017 edition of EN 16931. For companies in Estonia and Latvia, that means two separate checks, not one.

What’s the Difference Between EN 16931 and Peppol BIS Billing?

The confusion usually comes from the fact that both names get used interchangeably, even though they answer different questions. EN 16931 defines what data an invoice must contain (the invoice number, buyer and seller identifiers, VAT breakdown) and what each field means. Peppol BIS Billing is that standard’s CIUS, short for Core Invoice Usage Specification: the concrete implementation that adds a technical format (UBL or CII), mandatory identifiers, validation rules, and the profiles that decide how an invoice actually moves across the Peppol network. Put plainly, EN 16931 is the recipe, and Peppol BIS is how that recipe gets cooked in a specific kitchen.

	EN 16931	Peppol BIS Billing 3.0
What it is	semantic data model: what an invoice must contain	CIUS: the standard’s implementation for a specific network
Who sets it	CEN, the European standards body	OpenPeppol, Peppol’s governing organisation
Current version	EN 16931-1:2026 (approved 13 March 2026)	3.0.21 (mandatory from 17 August 2026)
What it governs	invoice fields and their meaning	identifiers, profiles, validation rules, code lists
Who feels it directly	national standards bodies, software vendors	companies sending or receiving invoices over Peppol

What Changed in EN 16931 in 2026?

EN 16931-1:2026 replaces the earlier EN 16931-1:2017+A1:2019 edition. CEN approved the standard on 13 March 2026 and published it on 18 March 2026, but that’s the start of the formal lifecycle, not the end. National standards bodies must publish or endorse it by 30 September 2026 at the latest, and any conflicting national standards must be withdrawn by 31 March 2029 at the latest. CEN also notes that the standard’s official reference in the Official Journal of the European Union, under Directive 2014/55/EU, is still listed as “expected”, not done.

The Transition Period Nobody Has Finalised Yet

According to the European Commission’s eInvoicing page, the 2017 edition has been formally withdrawn but stays compliant throughout the transition period. Concrete transition plans (how and when systems actually move from the 2017 version to the 2026 version) are still being worked out by national authorities and standards bodies. Who has to switch, and by when, isn’t yet fixed in any published document.

What Changes in Peppol on 17 August 2026?

Peppol BIS Billing 3.0.21 was published on 20 May 2026 and becomes mandatory to use from 17 August 2026. It brings several concrete changes.

A New Profile for Invoice Responses

A new optional profile, Profile 02, “Billing with Response”, is added for processes where the seller expects confirmation from the buyer on the invoice. Using this profile requires a separate SMP registration (SMP, short for Service Metadata Publisher, is the directory that shows which Peppol profiles a company supports) because the standard Billing profile doesn’t cover it.

Updated Validation Rules and Code Lists

The validation artefacts get updated too. UBL and CII version 1.3.16 was published on 10 April 2026, alongside a new code list release from 6 March 2026. Code list changes flow straight into validation rules, which only accept valid codes. As an example, currency codes ANG and BGN were dropped from the list and a new code, XCG, was added; several EAS (Electronic Address Scheme) identifier codes changed too.

Stricter Rules and a Corrected Field

Two general rules, PEPPOL-COMMON-R052 and PEPPOL-COMMON-R053, move from warning to error status and now apply to every profile. New warning rules were also added for Dutch identifiers (schemes 0106, 0190, 0217, 9944, and NL VAT numbers). These are warnings for now, but the documentation flags them as set to become mandatory error rules in a future release. And a fatal rule, PEPPOL-EN16931-R004, covering the CustomizationID field (the technical reference in the invoice header that shows which rule set the invoice was built against), was corrected.

Why Do Companies Mix Up These Two Updates?

Here’s the part worth separating clearly: Peppol BIS Billing 3.0.21 still describes itself in its own documentation as a CIUS built on the CEN/EN 16931:2017 standard. That’s not a typo. It means the Peppol update taking effect on 17 August 2026 does not automatically move your invoices onto the new EN 16931-1:2026 semantic model. The Peppol and EN 16931 updates are currently running on parallel but separate tracks, and the absence of any confirmed transition plan on the European Commission’s eInvoicing page shows that this integration is still in progress. If your software provider claims 3.0.21 “brings in the EN 16931-1:2026 requirements”, ask which source backs that up. Going by the current documentation, it doesn’t.

What Should Finance and IT Check Before the Deadline?

Before 17 August 2026, it’s worth working through this list:

• Update your validation tools and code lists to match the 3.0.21 release: old codes, like the dropped currency codes ANG and BGN, will no longer pass validation.
• Test how your system handles the CustomizationID field: the corrected rule PEPPOL-EN16931-R004 requires that this field not contain version information.
• Decide whether your business process actually needs an invoice response. If it does, Profile 02 requires a separate SMP registration before the deadline.
• If you don’t need Profile 02, still confirm that your existing SMP registration is valid and correct.
• Check your country-specific identifier data, especially if you deal with Dutch counterparties: schemes 0106, 0190, 0217, 9944 and NL VAT numbers get new warning rules that are set to become fatal errors in a later version.

What Does This Mean in Estonia and Latvia?

Estonia: Buyer Chooses, Standard Stays Flexible

In Estonia, since 2025, an accounting entity registered to receive e-invoices can require its supplier to issue the invoice electronically, unless the two parties have agreed otherwise. This “buyer chooses” principle was also extended to the private sector. According to guidance from the Ministry of Finance, Estonia allows the use of both the local Estonian e-invoice standard and the European standard, and that freedom of choice currently stays in place. Publishing EN 16931-1:2026 doesn’t change that underlying choice.

Latvia: A Phased Mandate Through 2028

Latvia’s situation is more specific: the structured e-invoice XML file must match the Peppol BIS Billing 3.0 specification. E-invoicing is mandatory from 1 January 2025 for transactions between the state and businesses (G2G, B2G, G2B), and in those same segments, sending invoice data to the State Revenue Service (VID) becomes mandatory from 1 January 2026. For business-to-business (B2B) trade, sending data to VID is voluntary between 1 January 2026 and 31 December 2027; from 1 January 2028, both issuing a structured e-invoice and reporting it to VID become mandatory for B2B transactions too.

What Deadline Sits Behind All This 2026 Work?

To put the amount of time actually available into perspective: the EU’s ViDA (VAT in the Digital Age) reform, Directive (EU) 2025/516, was adopted on 11 March 2025, but its cross-border B2B digital reporting requirements only apply from 1 July 2030. Member states that already run a domestic real-time reporting system get until 1 January 2035 to align their systems. In other words, the 2026 updates to EN 16931 and Peppol aren’t the ViDA deadline. They’re technical groundwork, while domestic rules (Estonia’s “buyer chooses” model, Latvia’s 2028 B2B obligation) stay on their own country-specific track, running separately from ViDA’s cross-border timeline.