Euro-Office’s announcement – which sees IONOS, Nextcloud and other companies coming together to create a European alternative to office productivity software – has predictably sparked a wave of comments. Most of these focus on the issue of licensing: is the code open source? Who controls the repository? What are the conditions for forking, modifying or implementing it?

While these are all valid questions, they fail to address the most important issue. The fact that almost no one is asking the question that matters tells us something significant about how the debate on digital sovereignty has been framed and who benefits from that framing.

A licence tells you who owns the software, while the format tells you who owns the data

A licence can be renegotiated, modified or updated. The history of FLOSS is full of projects that have changed governance models, divided communities, or changed course under new management. Licence terms are important, but they operate at the level of the software artefact.

The native document format operates at a completely different level. It is the encoding level of every document produced, archived, and exchanged by institutions that adopt the software. It is the invisible structure of administrative memory within which public documents exist for years, or even generations. It is the infrastructure.

If Euro-Office is supplied with OOXML as the default native format – even if it is wrapped in an open licence, hosted on European servers or governed by a European legal entity – every document drafted by public administrations, schools and institutions will be written in a format designed around the behaviour of a single vendor’s application.

OOXML is governed by a specification that is so complex and internally inconsistent that it compromises interoperability. As if that were not enough, it is optimised for backward compatibility with Microsoft Office rather than for seamless exchange between systems.

The licensing issue asks: who controls the code? The format issue asks: who controls the data? These are not equivalent situations. The latter has long-term implications for public archives, administrative continuity, and the practical significance of vendor independence.

For thirty years, the FLOSS and digital rights communities have been working on licences based on the fundamental principle that a licence equals freedom. This work has produced enormous value, but it has also created an unintentional blind spot.

Microsoft has spent decades conducting one of the most effective user education campaigns in the history of the software industry. However, what it has taught is dependency. Consequently, a generation of users, administrators, developers and even FLOSS advocates has grown up treating OOXML documents as the natural unit of document exchange — just like water flowing from a tap. OOXML files are not perceived as a lock-in mechanism, but as normal documents.

This is an incredible strategic achievement. Microsoft has managed to transform a proprietary file format, which was designed to replicate the behaviour of its own applications rather than enable transparent content exchange, into an interoperability standard.

Compatibility with the OOXML format is not viewed as a courtesy to the monopoly holder; rather, it has become a feature that alternative software must provide to prove its legitimacy. Lock-in has been transformed into an advantage: users are not trapped in Microsoft’s format; they are simply using the format that everyone else uses.

The FOSS community, which should be particularly vigilant about such dynamics, has often uncritically accepted Microsoft’s approach. Indeed, when evaluating an alternative productivity suite, the first question is often about the ability to open OOXML files rather than about the native format and whether it enables interoperability. Unfortunately, the alternative is judged according to criteria subtly dictated by Microsoft.

Consequently, format policy is treated as a secondary technical issue rather than the major political issue it really is. Meanwhile, Microsoft has pursued a precise and successful strategy of securing OOXML certification as an ISO standard to define it as ‘open’, while ensuring that licensing issues take precedence over format issues.

The result is that “supporting ODF” has become a box to tick rather than a specific commitment. This explains why all office suites today claim to support ODF. The practical implications of this support – such as whether ODF is the native or default format, or the format in which documents are created and stored without user intervention – are rarely considered, let alone addressed.

The test that matters

Euro-Office presents itself as a genuine European alternative: an infrastructure project for digital sovereignty. This claim deserves to be put to the test in terms of whether institutions will manage to free themselves from Microsoft lock-in, or if they will simply reproduce it under a different banner.

The test is simple and admits only one answer: ODF will be the native format of Euro-Office; the format in which documents are created, stored, and exchanged by default without user configuration or technical intervention.

Not: Euro-Office supports ODF because, in a nominal sense, everything supports ODF. Users can save in ODF format because this is a compatibility feature, not a commitment to true digital sovereignty.

If the answer is yes, then Euro-Office represents a significant structural break with the dominant proprietary format. However, if the answer implies “compatibility”, “user choice”, “transition paths” or “broad format support”, then Euro-Office is, regardless of the licence, a server migration that leaves Microsoft’s lock-in on data unchanged.

Digital sovereignty is not achieved by changing who hosts the software, but by changing the format in which data is encoded. European institutions, public administrations, and civil society organisations considering Euro-Office deserve a direct and immediate answer to this question before making any further commitments.

ODF has to be native, default, and by design.

Since its foundation, the Document Foundation has supported ODF as an open standard for document exchange. ODF (ISO/IEC 26300) is the only document format standard designed from the outset to ensure interoperability, long-term preservation, and total vendor independence.

The announcement of the Euro-Office is welcome news. The coalition is credible, the governance is sound and the timing is perfect. Europe needs office software, and The Document Foundation is delighted to see such significant players allocating resources to make it happen.

However, we have a question. It is not meant to be hostile, but it is the only question that matters.

What is the native document format of Euro-Office?

The press release promises full compatibility with Microsoft formats. We are well aware of the logic behind migration: organisations moving away from Microsoft need to be certain that their documents will survive the transition. But “full compatibility with Microsoft formats” is certainly not a definition of sovereignty, but rather the definition of a different kind of dependency.

OOXML is a format designed, controlled and managed solely by Microsoft. Building a European office suite prioritising compatibility with OOXML means ensuring that the European document infrastructure remains subordinate to architectural decisions made in Redmond. The hosting moves to Europe, but the lock-in remains in Redmond.

The alternative exists, is mature and is a law in several European jurisdictions. ODF, the Open Document Format, is an ISO standard developed through an open and transparent process, which is not controlled or managed by a company. The German Deutschland-Stack has made it mandatory, and the EU Commission has approved it. It is not the LibreOffice format, but a European public good.

The Euro-Office press release does not mention ODF even once.

We are not asking Euro-Office to abandon support for Microsoft’s proprietary format. LibreOffice itself reads and writes OOXML: compatibility is a necessity for users, not an ideological concession. We are asking whether ODF will be the native format, the one in which documents are created, archived and exchanged between European public administrations.

This distinction is fundamental, and the time to define the native document format is now, before the architecture is finalised and the implementations take place. If necessary, we are here to help with the deployment of the ODF standard as native document format.

The coalition has the credibility and resources to build something truly innovative. We hope it will use them to build a project of sovereignty and not merely a tool for server migration, flying a European flag but with a lock-in firmly rooted in Redmond.

The Document Foundation is a non-profit foundation and the home of LibreOffice, the world’s leading open-source office suite. LibreOffice implements ODF as its native format and supports a wide range of document formats, including the import and export of OOXML.

The door to digital sovereignty is open, please come in

For decades, a community of developers, activists, researchers and public officials has quietly worked on the idea that free and open-source software based on open standards is not only the best technical choice, but also the only one compatible with democratic governance.

We have created the necessary tools, overseen migrations and provided user training. We have also drafted policy documents and presented them to committees.

We have documented the consequences of public documents being readable only by software developed in a single country, managed by a single company and subject to the laws of a different jurisdiction, as well as the commercial decisions of a board of directors.

The French gendarmerie, the Austrian Ministry of Defence and the German state of Schleswig-Holstein – to name but a few examples – have taken action, alongside regions, provinces and cities across Europe.

We have always been here, and not with a product to sell, but with the knowledge, patience and sincere conviction that public institutions belong to the public, and that this also applies to their digital infrastructure.

Sometimes we were listened to, but far more often we were merely tolerated, at best with a smile that seemed to say: “I know, but what can I do about this?”

And now, suddenly, the situation has changed, and not because the arguments have changed – there was no need for that – nor because the technology has changed, as it was already excellent.

The situation has changed because the geopolitical balance has shifted, and the dependence that once seemed a convenience now appears for what it has always been: a structural vulnerability.

We are glad that this moment has arrived, and we like to think that this clarity – which the evidence never managed to achieve – is also down to us, and not just the geopolitical crisis.

But we ask European citizens, and through them those who govern European countries, to understand one extremely important thing: the door to digital sovereignty does not open simply by choosing different software, but by understanding what sovereignty actually entails.

It requires open document formats, not as a preference, but as a legal and technical guarantee that a document produced today will be readable in thirty years’ time, by any compliant application, without the permission of any company. The format is not a detail, but the foundation.

It requires open fonts, because a document displayed differently on different systems is not an interoperable document, regardless of the standard it claims to follow. The display layer is just as important as the data layer.

It requires continuity of expertise: the people and institutions that have carried out this work, often without recognition and sometimes without resources, are not a lobby to be managed but a valuable repository of knowledge to be engaged.

It requires honesty about what “open” means. A coalition that speaks of digital sovereignty but chooses as its default document format one designed to replicate the behaviour of proprietary software is not building sovereignty but a new dependency under a different banner.

We have been here for years, and we will still be here for years to come.

The FLOSS ecosystem did not need a geopolitical crisis to believe in open standards. We have always believed in them, because they are right—technically, legally, and democratically.

Now that Europe is ready, we have just one request: listen to us carefully, unlike what you have done in the past. The lesson is not simply “use free and open-source software”. The lesson is: understand why it is important, and understand it thoroughly.

The tools exist, the knowledge exists, and above all, the community exists.

What happens next will depend solely on you: Europe’s digital sovereignty could become a genuine architectural commitment or remain yet another rebranding of dependency.

We hope, and would like to be sure, that you choose the first option.

Over the coming weeks, four articles will explore these topics in depth: the architecture of document formats, the hidden politics of font rendering, lessons learned from real-world migration experiences, and what a credible European policy on open standards would actually look like. We invite you to read them.