Table of Contents
On June 9, 2026, at exactly 12:00 CEST, a GitHub repository went public. It contained source code, build instructions, and pre-built Docker images for something that a coalition of European technology companies had been quietly assembling for months: Euro-Office, an open-source office suite built to be Europe’s answer to Microsoft 365 and Google Workspace.
The launch was coordinated. Deliberate. And immediately controversial.
Within hours, LibreOffice’s parent organization had fired a public broadside accusing it of being a “de facto ally” of Microsoft’s own lock-in strategy. Within days, the company whose codebase Euro-Office forked had announced legal action. And underneath all of it, a much larger political story was unfolding — one that had started not on June 9 but four days earlier, when the European Commission unveiled something that will shape software procurement across the continent for the next decade.
This is not just a story about an office suite. It’s a story about who gets to own the future of European software infrastructure — and what “digital sovereignty” actually means in practice.
Europe’s Biggest Bet on Open Source
Four days before Euro-Office launched, on June 3, 2026, the European Commission presented what it called the European Technological Sovereignty Package. If you missed the headline, you could be forgiven — it landed quietly between the usual cycle of geopolitical news — but the substance of what was announced is genuinely significant.
The package bundles four major initiatives:
The Chips Act 2.0 pushes to accelerate European semiconductor manufacturing, aiming to reduce dependency on Asian and American chip supply chains. The Cloud and AI Development Act (CADA) introduces an open-source-first principle: when EU public administrations buy cloud or AI software, they must evaluate open-source alternatives first, and choose them when functionally adequate. The EU Open Source Strategy sets a concrete target of 30 million active users of open-source collaboration tools by 2030. And the Strategic Roadmap for Digitalisation and AI in Energy ties all of this to the bloc’s broader industrial ambitions.
The political logic behind all of it is hard to argue with, even if you’re skeptical of how well Brussels actually executes on these things. For decades, the daily operations of European governments — their emails, their spreadsheets, their document archives, their procurement systems — have run on Microsoft and Google infrastructure. Data flows to servers in the United States. Licensing fees flow to American shareholders. When those companies change their terms, raise prices, or comply with foreign government data requests that conflict with European law, the EU finds itself with essentially no leverage.
CADA changes the procurement calculus in a fundamental way. The EU Digital Identity Wallet, a piece of infrastructure that will eventually be used by hundreds of millions of European citizens, is now mandated to be open source by design. That is sovereignty built into the architecture, not bolted on as an afterthought.
What makes this announcement different from previous EU digital strategy documents — and there have been many — is the explicit linkage between the pieces. European chips powering European cloud infrastructure, with demand from that infrastructure supporting European chipmakers. It is a deliberate industrial loop, and it requires European software to fill the gap between the hardware ambitions and the services that run on top.
That is where Euro-Office enters the picture.
What Euro-Office Actually Is
Euro-Office is, technically speaking, a fork of OnlyOffice — the open-source productivity suite that has been popular in the self-hosting and enterprise Linux communities for years, primarily because of how well it handles Microsoft Office file formats. When you open a complex .docx file with heavy formatting, embedded objects, or intricate spreadsheet formulas in OnlyOffice, it tends to look right. That is not something that can be said about every open-source office suite, and it matters enormously for organizations that need to collaborate with people using Microsoft’s tools.
The engineering choice to fork OnlyOffice rather than build on LibreOffice — the other main open-source office suite — was deliberate, and it is at the centre of the controversy that erupted on launch day. But more on that shortly.
The consortium behind Euro-Office is not a scrappy startup. It is a coalition of established European technology companies: Nextcloud and IONOS from Germany, XWiki from France, OpenProject, Soverin, Abilian, BTactic, OpenXchange, Eurostack, and Office.eu. Proton — the Swiss privacy company behind ProtonMail and ProtonVPN — is also part of the group.
That combination of names matters. Nextcloud alone claims tens of millions of users. IONOS is one of Europe’s largest cloud infrastructure providers. These are not companies that launch projects and abandon them after six months. There is institutional weight here.
At launch, Euro-Office offers what you would expect from a mature collaborative office environment: real-time co-editing of documents, spreadsheets, and presentations, full compatibility with DOCX, XLSX, and PPTX formats, and a live demo at euro-office.eu. For organizations and developers who want to run it themselves, the complete source code is on GitHub alongside pre-built container images. Nextcloud Hub 26 Spring — released the same day — ships with Euro-Office as an available document editor option, sitting alongside the existing Collabora Online integration.
The Messy Divorce from OnlyOffice
The fork from OnlyOffice did not happen calmly. The consortium split from the upstream codebase in March 2026 after what it described as a deteriorating relationship with Ascensio System SIA, the Latvian company that develops and commercializes OnlyOffice.
The specific grievances were recognizable to anyone who has watched a successful open-source project gradually become more focused on its commercial edition than its community: pull requests going unaccepted, build documentation becoming increasingly unreliable, and features being removed from the open-source codebase without community consultation. The pattern is not unique to OnlyOffice. It is the same dynamic that caused Elasticsearch to be forked into OpenSearch, Redis to be forked after its license change, and Terraform to be forked into OpenTofu after HashiCorp’s pivot to BSL. When an open-source project’s commercial ambitions start crowding out its community commitments, the community eventually walks.
Ascensio’s response was not measured. Within five days of the fork being announced publicly, the company declared that Euro-Office constituted a license violation and initiated legal proceedings against the consortium. The case is unresolved at the time of writing, and depending on how it plays out, it could have real implications for the project’s distribution and long-term trajectory.
What is already clear is that the underlying codebase — OnlyOffice is licensed under the AGPLv3 — is out in the open, being actively maintained and developed by a group of companies with significant resources. Whatever happens legally, the software exists and is running.
The Deeper Argument: Who Owns the Document Standard?
The legal dispute with OnlyOffice was almost expected. The argument with the Document Foundation was not — or rather, it surfaced a tension that has been simmering in the open-source world for twenty years and that nobody has successfully resolved.
The Document Foundation is the non-profit organization behind LibreOffice. They have been fighting for open document standards since long before it was politically fashionable, and they came out against Euro-Office hard, before it even officially launched. The Register’s headline captured the tone: “LibreOffice brands Euro-Office a ‘de facto ally’ of Microsoft’s lock-in strategy.”
The accusation sounds dramatic. The argument behind it is not unreasonable.
Euro-Office defaults to saving files in OOXML — Microsoft’s Office Open XML format, the standard that gives you .docx, .xlsx, and .pptx files. OOXML is, technically, an ISO-ratified international standard. That ratification process was also, notoriously, one of the most contested in ISO history. The specification runs to over 6,000 pages. Implementing it fully and correctly requires access to decades of Microsoft-internal behavior documentation that simply does not exist in the public standard. In practice, only Microsoft’s own software has ever fully implemented it.
The Document Foundation’s argument is that by defaulting to OOXML, Euro-Office is encoding every document its users create in a format that Microsoft ultimately controls. You might not be running Microsoft software. You might not be paying Microsoft a cent. But your .docx file is still a Microsoft artifact, dependent on Microsoft’s interpretation of what that format means. That is not sovereignty — it is dependence in a different coat.
The Euro-Office consortium’s counter-argument is the pragmatic one: you cannot switch the entire world’s document infrastructure to ODF by default and expect anyone to adopt your product. European governments still need to send documents to citizens who open them in Word. Schools still receive assignments in formats that parents edit on whatever laptop they have at home. Businesses still collaborate with partners across borders who have not made any decisions about open-source document formats. A sovereignty solution that requires interoperability to go through a conversion step every single time someone sends a file outside the organization is a solution that will never actually get deployed at scale.
Both positions are genuinely right about something. The Document Foundation is correct that format sovereignty requires ODF. The consortium is correct that ODF as a default would kill adoption before the project had a chance to prove itself. Neither side has a clean answer, because the problem itself is genuinely hard. The 20-year format war between ODF and OOXML is not resolved by Euro-Office launching — it is simply being replayed in a new arena, with higher stakes and better-funded players.
What It Actually Changes
The thing worth watching here is not whether Euro-Office wins or loses the immediate controversy. It is whether the broader EU policy framework — CADA, the Open Source Strategy, the procurement mandates — creates the conditions for a real shift in how European institutions buy and use software.
The implications of CADA in particular are underappreciated. An “open-source-first” procurement principle, applied consistently across EU public administrations, represents an enormous potential customer base that has historically been locked into Microsoft Enterprise Agreements renewed on autopilot. If even a fraction of those institutions genuinely evaluate open alternatives and choose them — not because of ideology but because the software is good enough and cheaper — the funding dynamics of the entire European open-source ecosystem change.
Projects that have historically scraped by on donations and small commercial tiers suddenly have access to multi-year government contracts. That means full-time engineering teams. That means proper security audits. That means better documentation, faster bug fixes, and the kind of long-term roadmap certainty that convinces enterprise IT departments to take the risk on something that is not Microsoft.
Euro-Office is not the only beneficiary of that shift. Nextcloud, which integrates Euro-Office and has been building for this moment for years, stands to gain significantly. So does the broader ecosystem of European-made open infrastructure: Forgejo for code hosting, Mastodon for communication platforms, Matrix for secure messaging, Jitsi for video calls. The EU’s 30 million active open-source collaboration tool users target by 2030 is not achievable without pulling all of these threads together.
Whether that vision materializes depends enormously on implementation — something Brussels has a mixed historical record on. But the political will is clearly present in a way that it was not five years ago, and the timing of Euro-Office’s launch alongside the Tech Sovereignty Package announcement was not accidental.
An Interesting Moment
Euro-Office 1.0 is not a finished product in the way that Word 2026 or Google Docs is finished. It is a fork of a codebase with unresolved licensing questions, backed by a political agenda that may or may not survive contact with the European Parliament’s legislative process. It is launching into a market where the incumbent has 30 years of inertia on its side and a near-unlimited advertising budget.
It is also the most serious European attempt in a generation to answer a question that actually matters: what happens to our documents, our data, and our software supply chain if we do not build alternatives?
The launch-day controversies — the LibreOffice argument about OOXML, the OnlyOffice lawsuit, the inevitable comparisons that will favor Microsoft on feature count for the next two years — are real. But they are also beside the point if the bigger story plays out the way its architects intend. A well-funded, consortium-backed, EU-policy-aligned open-source office suite is a fundamentally different animal from the open-source alternatives that came before it. Those alternatives asked users to accept trade-offs as a matter of principle. Euro-Office is being built on the premise that you should not have to.
Whether it delivers on that promise is a question for future versions. For now, the code is public, the Docker images are ready, and the most interesting office suite story in years is just getting started.
The Euro-Office source code, build instructions, and container images are available at github.com/Euro-Office. The Nextcloud Hub 26 Spring release notes cover integration steps for existing Nextcloud deployments.
