"Isn't there an office suite from the federal government that replaces Microsoft?" The suite in question is openDesk. Businesses in the Recklinghausen district ask me this, and right now there are two reasons: since 1 July 2026, higher Microsoft list prices apply, and Office 2021 and Office LTSC 2021 have been out of support since 13 October 2026.
My short answer: openDesk covers email, calendar, files, office apps in the browser, chat and video conferencing. But it is built as a replacement, not as an add-on: running it alongside Microsoft 365 is possible, integrating the two is not. For most small businesses, openDesk is therefore a candidate for a pilot project in 2027, not something to switch to this autumn. What the price increase means for your contract is covered in my Microsoft 365 licence audit.
As of: 20 October 2026, openDesk 1.19.2. I do not run openDesk myself; this assessment is based on vendor information, documentation and a study from Zurich. This article is not legal advice.
Who is behind openDesk?
openDesk comes from the Zentrum für Digitale Souveränität der Öffentlichen Verwaltung (ZenDiS, the centre for digital sovereignty in public administration), a limited company 100% owned by the German federal government and based in Bochum, right in the Ruhr area. It was launched in October 2024, and according to ZenDiS, 100,000 public administration workstations are now equipped with it. BWI, the Bundeswehr's IT service provider, has signed a framework agreement (PDF, in German) for openDesk with an initial term of seven years.
openDesk is made for public authorities: according to its FAQ, it is "designed for the wider public sector". Private-sector cloud providers and IT service providers have only been allowed to build their own offerings based on the Enterprise Edition since 23 September 2026.
Which openDesk module replaces which Microsoft app?
openDesk bundles open-source products behind a single login. The "maturity" column summarises what the Zurich study and openDesk's own documents say, not my own tests.
| Microsoft 365 | openDesk module (product) | Maturity according to sources |
|---|---|---|
| Outlook, Exchange | Email, calendar, contacts (Open-Xchange) | email, calendar good to very good; desktop Outlook not listed as a client |
| OneDrive, SharePoint | Files (Nextcloud) | good to very good |
| Word, Excel, PowerPoint | Office in the browser (Collabora Online) | word processing, spreadsheets good to very good; macros limited |
| Teams | Chat (Element), video (Nordeck, Jitsi) | good to very good; no Teams bridge, no external telephony |
| Planner, wiki, OneNote | OpenProject, XWiki, Notes (Docs) | not rated on the Zurich project page |
| Entra ID | Nubus (Univention) | own directory; Entra ID only via a workaround |
| Copilot | AI writing assistance in Collabora and Notes | only with your own AI endpoint, no AI model included |
| Power Platform, Intune, Defender | no equivalent | missing |
What openDesk cannot do today
The clearest account of its limits comes from an evaluation by the City of Zurich with the Bern University of Applied Sciences: around 70 tests in four iterations during the project period of August 2025 to January 2026, using versions 1.7.0 and 1.8.0. According to the study, openDesk covers the basic functions of an office workstation "well to very well". However, "a rapid, complete replacement of M365 is not currently possible". What is missing:
- its own desktop and mobile apps (the openDesk FAQ does list apps from Element, Nextcloud and Collabora),
- external telephony and an equivalent to the Power Platform,
- automated device and client management as with Intune,
- comprehensive security features comparable to Microsoft Defender.
In the versions tested, full-text search in documents and full macro support were also missing; according to the study, both are being addressed continuously. According to the FAQ, integrated audit-proof archiving is not currently part of openDesk.
The study puts the online licences at around CHF 230 per year, currently more than 50% more expensive than comparable Microsoft licences; that is a Zurich estimate, not a German list price. It recommends a proof of concept; any migration would have to be gradual, over several years. One side note strikes me as important: the migrations in Schleswig-Holstein mostly started from older on-premises systems, not from Microsoft 365. For me, this means: if you use Teams, Intune and Defender today, you give up more by switching than a business coming from an old Exchange server.
Why openDesk and Microsoft 365 don't work together
A mixed setup seems the obvious choice: openDesk for most staff, Microsoft for special cases. The interfaces hardly allow it:
- Outlook: openDesk's interface overview lists IMAP programs such as Thunderbird for email, and no external connection for calendar and contacts. Outlook does not appear there as a client, nor in Open-Xchange's product guide.
- Teams: Element no longer sells its bridge between Element and Teams.
- User accounts: openDesk has to know every account itself; with only a few users, the documentation says this can also be done by hand. For the recommended sync from LDAP or Active Directory, Entra ID alone also requires Azure AD Domain Services, because it does not offer LDAP.
My conclusion: a permanent mixed setup means two calendars, two chats and two user directories. If you go with openDesk, do it for a clearly defined area or all the way.
What the free Community Edition really costs
The Community Edition can be downloaded free of charge from openCode.de. According to the FAQ, you run it "independently", with support from the community. For production use, however, the technical documentation recommends the Enterprise Edition, which gets some features and certain security patches exclusively. It is built on Kubernetes, a container platform that needs looking after in its own right.
The release posts on the openDesk blog show how much looking after that is: between 19 August and 19 October 2026, six versions appeared on the newest branch at the time (1.18, 1.18.1, 1.18.2, 1.19, 1.19.1 and 1.19.2), three of them with security updates. For the vulnerability in XWiki, with a CVSS score of 9.3 out of 10, ZenDiS writes: "We recommend that you update immediately." If you run it yourself, you install all of this yourself; only the licence is free.
Schleswig-Holstein uses individual building blocks instead of openDesk, including the same mail software: on 2 October 2025, the state administration completed the move of more than 40,000 mailboxes from Exchange to Open-Xchange and Thunderbird. According to Digital Minister Dirk Schrödter (c't), disruptions during the switch were explicitly not caused by the open-source software; a load balancer in the data centre had been misconfigured. You can estimate what a day without email costs with the downtime cost calculator; how much time your own mail server demands is covered in self-hosted mail server or Microsoft 365.
How can a small business get openDesk today?
The Enterprise Edition with fixed SLAs is designed for large organisations with over 500 users. More interesting for small businesses are the partners in the partner programme; ZenDiS named the first three (in German) on 13 October 2026:
- STACKIT offers openDesk as SaaS: pilot packages are available now, and the production offering is due to launch in early 2027.
- B1 Systems and DACHS IT handle setup and operation as system integrators, as SaaS or at the customer's site; B1 Systems explicitly mentions environments for small groups as well.
So in autumn 2026, the options are a pilot package, an integrator or the Community Edition with a service provider.
Four questions that decide the switch
- Do processes depend on Excel macros or add-ins? Then you will still need Microsoft Office, at least for those.
- Can you manage without Outlook? If you need Outlook with calendar and contacts, that rules it out.
- Where are your user accounts? A local Active Directory can be synced directly; Entra ID alone only via a workaround.
- Who will run it? Without someone who has Kubernetes and updates under control, only a partner offering is an option.
If you simply want a different cloud, the comparison of Microsoft 365 and Google Workspace covers the second big option.
My recommendation: answer the four questions now and plan a pilot project with a small group for 2027, as the Zurich study also suggests. openDesk can already be a fit today for businesses that work almost entirely in the browser, need no macros, manage their accounts locally and have a service provider to run it.
Still have questions about openDesk?
What does openDesk cost a small business?
The Community Edition is free; running it is not. According to ZenDiS, prices for the Enterprise Edition are only available "on request", and the CHF 230 is a Zurich estimate, not a price for Germany.
Can I keep editing Word and Excel files?
Yes, according to the FAQ openDesk offers "compatibility with common Microsoft Office file formats". The limit is macros; check your most important templates in a test environment.
Can I bring my email over from Microsoft 365?
Yes, according to the openDesk documentation via the paid audriga service, with up to 50 accounts per CSV upload. However, the required migration mode is missing from the Community Edition.
Is there an AI like Copilot?
Partly. Collabora Online and Notes have AI writing features, but openDesk does not include an AI model: you bring your own endpoint, model and API key. ZenDiS has so far only shown a cross-application AI as a proof of concept, in October 2026.
Want to know where your business stands on macros, Outlook and user accounts? Then let's go through the four questions together, with no outcome decided in advance. More about my IT support for SMEs in Recklinghausen.
Note: The articles on this blog are produced with the help of AI and are editorially reviewed before publication. Editorial responsibility lies with Emre Yurtbay (see the legal notice).