EN 16931 - CEN/TC 434

This page tries to give a rough overview on CEN/TC 434 and EN 16931, how it belongs together and where to find what.

Note: this is not an official page. This is just what I'm collecting...

The EN 16931-1:2017 was published on October 17th 2017 in the OJ. That means that since April 18th 2019 most public procuring entities must be able to accept e-Invoices complying to the UBL and CII syntax requirements defined in CEN/TS 16931-3-2 and CEN/TS 16931-3-3!


In the beginning was directive 2014/55/EU. Article 3 starts with:

The Commission shall request that the relevant European standardisation organisation draft a European standard for the semantic data model of the core elements of an electronic invoice (the ‘European standard on electronic invoicing’).

This lead CEN to start PC 434 (Project Committee) which was later transfered to a TC (Technical Committee) → CEN/TC 434.

Structure of work

The TC had 6 working groups concerning with the following topics:

  1. A European standard (EN) on the semantic data model for the core elements of an electronic invoice

    Created: EN 16931-1:2017 Part 1: Semantic data model of the core elements of an electronic invoice

  2. A Technical Specification (TS) on a limited number of invoice syntaxes (formats) which fully comply with the EN

    Created: CEN/TS 16931-2:2017 Part 2: List of syntaxes that comply with EN 16931-1

  3. A Technical Specification (TS) on the syntax bindings, i.e. information specifying how the semantic data model could be represented in the listed syntaxes (formats) and their automatic validation artefacts


    • CEN/TS 16931-3-1:2017 Part 3-1: Methodology for syntax bindings of the core elements of an electronic invoice
    • CEN/TS 16931-3-2:2017 Part 3-2: Syntax binding for ISO/IEC 19845 (UBL 2.1) invoice and credit note
    • CEN/TS 16931-3-3:2017 Part 3-3: Syntax binding for UN/CEFACT XML Industry Invoice D16B
    • CEN/TS 16931-3-4:2017 Part 3-4: Syntax binding for UN/EDIFACT INVOIC D16B

  4. A Technical Report (TR) covering the guidelines on interoperability of electronic invoices at the transmission level, taking into account the need of ensuring the authenticity of the origin and the integrity of the electronic invoices’ content

    Created: CEN/TR 16931-4:2017 Part 4: Guidelines on interoperability of electronic invoices at the transmission level

  5. A Technical Report (TR) covering the guidelines on the use of sector or country extensions (as described in the Recommendation of the European Multi-stakeholder Forum on e-Invoicing) in conjunction with the European standard, including a methodology to be applied in the real environment

    Created: CEN/TR 16931-5:2017 Part 5: Guidelines on the use of sector or country extensions in conjunction with EN 16931-1, methodology to be applied in the real environment

  6. A Technical Report (TR) covering the result of the test of the European standard with respect to its practical application for an end user

    Created: CEN/TR 16931-6:2017 Part 6: Result of the test of EN 16931-1 with respect to its practical application for an end user

Working with the EN 16931

From a practical point of view this norm means, that all public entities performing public procurement cannot reject electronic invoices from April 18th 2019 if they are retrieved in UBL or CII formats complying to the norm. Certain receivers have an additional 12 month to comply to the requirements, ending up on April 18th 2020.

Because life would be too easy if EN 16931 was a "one size fits all" solution, there are already a lot of so called CIUSs developed. A CIUS is an additional specification on top of EN 16931-1:2017 that narrows certain fields for certain use cases. The methodology how a CIUS is defined, can be found in CEN/TR 16931-5:2017.

An unofficial self-declaration based list of CIUSs is provided by CEF. One upcoming task of CEN/TC 434 is to establish an official registry of CIUSs.

Another project in CEN/TC 434 tries to setup a more elaborate registry for CIUS, Extension and Code list. The current effort can be seen at https://www.helger.com/registry434/ but please bare in mind, that this is work in progress. Details will follow.

How to get the norm?

You should be able to download the standard (at least parts 1 and 2) for free from your local standardization body. E.g. at Austrian Standards (ASI) ÖNORM EN 16931-1: 2017 11 01 and ONR CEN/TS 16931-2: 2017 10 15 can be downloaded free of charge, whereas parts 3, 4, 5 and 6 are payable documents.

If you are impatient and would ask me what documents to buy I would suggest the following ones:

  • EN 16931-1:2017
  • CEN/TS 16931-3-1:2017
  • One or more of CEN/TS 16931-3-2:2017, CEN/TS 16931-3-2:2017 or CEN/TS 16931-3-3:2017 - depending on what you want to implement
  • CEN/TR 16931-5:2017

Technical requirements

Mostly it is about validating, if a UBL or CII documents fulfills all the requirements from the norm. Therefore the following steps need to be performed:

  1. Validate the e-Invoice against the XML Schema of UBL 2.1 or CII D16B - depending on the namespace URI of the XML root element
  2. Apply the Schematron rules for the correct syntax. Schematrons are available from GitHub. Up to and including v1.2.3 the validation artefacts were licensed under the Apache 2 license, since version 1.3.0 they are licensed under the EUPL 1.2. A fully working open source validation engine is available at https://github.com/phax/ph-bdve/ licensed under the business friendly Apache 2 license. It supports the official EN 16931 validation artefacts for UBL, CII and XML EDIFACT invoices besides a lot of different standards.
  3. If you need to follow a certain CIUS, apply the Schematrons of the CIUS in the correct order as well. As there are currently no published CIUSs, there is also no predefined tool support for this.


CENComité Européen de Normalisation - European Committee for Standardization
CEN/TCCEN Technical Committee - working group
CIIUN/CEFACT Cross Industry Invoice - XML representation of an invoice
CIUSCore Invoice User Specification - A specification based on EN 16931-1:2017 that defines certain elements more narrow
ENEuropean Norm - has tighter binding than TR and TS
EN 16931European Norm instance with ID 16931 - this is the EN that contains the semantic data model for electronic invoices in Europe
TRTechnical Recommendation - has lower binding than EN and TS
TSTechnical Specification - binding between EN and TR
UBLISO/IEC 19845 Universal Business Language - XML representation of an invoice

External Links

This chapter contains some external links that you might consider helpful:

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