Leave Microsoft 365 like the Dutch tax office?
What the Dutch tax office decided
In a letter to Parliament, the State Secretary for Finance, Eelco Eerenberg, announced that the Belastingdienst (the tax authority), Customs and Toeslagen (the benefits service) are abandoning their migration to Microsoft 365, a choice made in 2025. Instead:
- 2027: email and calendars will run on tax-office servers, or on servers it controls;
- late 2027 and 2028: file storage and team collaboration tools will move to European open-source solutions;
- existing licences will be reused as far as possible, to limit investment.
The reasons given: a “more autonomous” digital workplace in the current geopolitical context, and the advice of a government expert committee (the Adviescollege ICT-Toetsing) recommending not depending on a single supplier and looking for a solution function by function. The tax office also acknowledges a weak point: some archiving functions included in Microsoft 365 do not exist on its own servers, and the State Secretary is to come back to this.
It is not an isolated case. Other European administrations have started the same move, and in an earlier article we described how an SME can leave Big Tech step by step.
What does not apply to your SME
The Dutch tax office has data centres, hundreds of IT staff and a multi-year timetable. A ten-person SME has none of that. Replacing Microsoft 365 with a server in a cupboard, with nobody to update or back it up, would be riskier than staying.
What does apply, however
Prices go up without asking you
On 1 July 2026, Microsoft raised its business subscriptions: Business Basic went from about 6 to 7 dollars per user per month, Business Standard from about 12.50 to 14 dollars. The Copilot assistant comes on top at 21 dollars per user per month in its version for companies with 300 people or fewer (previously 30 dollars). For fifteen users, the annual bill for Standard + Copilot reaches 6,300 dollars excluding tax (15 × 35 dollars × 12 months).
That's not a scandal: it's how subscriptions work. But the more of your tools depend on the same supplier, the less room you have to negotiate or leave.
Your data falls under US law
Even when hosted in Europe, data entrusted to an American company can be demanded by US courts under the CLOUD Act. For most SMEs, this is a theoretical risk. For a law firm, an accountancy practice or a medical office, it is a question worth asking.
AI deepens the dependence
Copilot works with Word, Excel, Outlook and Teams, and with your data stored at Microsoft. The more you use it, the harder it becomes to switch tools.
The alternative has taken a step forward: ONLYOFFICE 10
On 13 October 2026, the publisher of the open-source office suite ONLYOFFICE released version 10, with an AI assistant in all its editors (documents, spreadsheets, presentations, PDF): summarise, rewrite, translate, correct, analyse a table. The difference with Copilot fits in one sentence: you choose which AI it uses. Installed on your own servers, it can be connected to an online service of your choice or to a model running on your premises (with Ollama, for example), in which case your documents never leave the company (see our article on local AI, without the cloud, in French).
What you should know before getting carried away:
- the Community edition is free, intended for a small team (ONLYOFFICE recommends it for up to 20 users); beyond that, or for support and an administration console, you need the paid Enterprise edition;
- AI is not included “ready to use” in the open-source versions: it has to be configured separately, and a local model needs a fairly powerful PC or server;
- ONLYOFFICE opens and saves Word, Excel and PowerPoint files, but complex macros and some advanced layouts can cause problems;
- it combines with Nextcloud (storage, sharing, calendar, contacts) to form a complete workplace.
In practice: three options
| Option | What it costs | The risk |
|---|---|---|
| Stay on Microsoft 365, change nothing | The subscription, and its future increases | Growing dependence, especially if you add Copilot; no fallback |
| Stay, but keep an exit door | Half a day of inventory, then choices at each renewal | Low: you know what could move elsewhere and at what price, you keep your files in open formats and your backups outside Microsoft |
| Migrate all or part (Nextcloud, ONLYOFFICE, European email) | Setup, hosting (with a European host or in-house), maintenance | Medium if poorly prepared (training, compatibility, backups); low with a plan and a provider who handles follow-up |
When staying on Microsoft 365 is the right choice: your business software depends on it, your team lives in Teams and in Excel files full of macros, or nobody will maintain another solution. In that case, the right decision is the second row of the table.
Example (illustrative case): an eight-person surveying firm pays for Microsoft 365 Business Standard and is wondering about adding Copilot. The inventory shows that three people really use Teams, everyone uses Outlook, and shared files are mostly PDF plans and simple spreadsheets. Decision: email stays with Microsoft for now; storage and sharing move to a Nextcloud hosted in Belgium, with ONLYOFFICE and a local AI assistant to summarise and rephrase; six Business Standard licences downgraded to Business Basic. The “full exit” file stays open for the next renewal.
For your IT person
- Inventory before deciding: licences per user and actual usage (activity reports in the Microsoft 365 admin centre), dependencies (VBA macros, Outlook add-ins, Teams integrations, business software on SharePoint).
- ONLYOFFICE Docs 10.0: released 13/10/2026; “AI Tools” tab in every editor; when self-hosted, AI provider of your choice, including a compatible local server (Ollama); central AI settings in the administration console of the Enterprise and Developer editions.
- Nextcloud + ONLYOFFICE: official connector app in the Nextcloud catalogue; plan the ONLYOFFICE document server separately, behind an HTTPS proxy.
- Gradual exit: storage first (OneDrive/SharePoint to Nextcloud), then calendars and contacts (CalDAV/CardDAV), email last (IMAP migration, MX, SPF, DKIM, DMARC records).
- Backup: whatever you decide, a copy of your data outside the supplier (3-2-1 rule, see protecting your data).
Test yourself
At ExsIT
The first contact is free: we listen to your needs, then propose an action plan. Inventory of your licences and their actual use, three-year cost calculation, and, where it makes sense, setting up Nextcloud and ONLYOFFICE, hosted in Belgium or on your premises, with follow-up and backups.
Sources
Finnegan, M. (2025, November 19). Microsoft drops M365 Copilot price for SMBs, upgrades free Copilot Chat. Computerworld. https://www.computerworld.com/article/4093224/
Gupta, A. (2025, December 5). Microsoft to raise Microsoft 365 business prices by up to 33% from July 2026. TechInformed. https://techinformed.com/microsoft-to-raise-microsoft-365-business-prices-by-up-to-33-from-july-2026
Hupkens, H. (2026, October 6). Belastingdienst stopt met de migratie naar de Microsoft 365-cloud. iBestuur. https://ibestuur.nl/digitale-weerbaarheid/digitale-veiligheid/belastingdienst-stopt-migratie-naar-microsoft-365-cloud
ONLYOFFICE. (n.d.). Compare ONLYOFFICE Docs editions. https://www.onlyoffice.com/compare-editions
Rudra, S. (2026, October 13). With 10.0 release, ONLYOFFICE goes all in on AI, making it the most modern office choice for team collaboration. It's FOSS. https://itsfoss.com/news/onlyoffice-docs-10-release/
Techzine. (2026, October 6). Fiscus stopt Microsoft 365-migratie, kiest on-premises en open source. https://www.techzine.nl/nieuws/applications/582507/fiscus-stopt-microsoft-365-migratie-kiest-on-premises-en-open-source/