Dutch Tax Office Drops Microsoft 365 Cloud for Own Servers and Open Source
The Dutch tax and customs administration has abandoned its plan to migrate to Microsoft 365 in the cloud. Instead, its office software will run on servers it controls, utilizing European open-source tools. This shift was announced by State Secretary for Finance Eelco Eerenberg in a letter to the Dutch parliament.
The Change in Plan
Initially, in October 2025, the agency intended to adopt Microsoft 365, considering it the sole viable option at the time. However, in June 2026, Secretary Eerenberg stated that the decision would be reviewed. This review led to a pause in the rollout on July 9th.
The decision was influenced by a report from the Adviescollege ICT-toetsing, the government's ICT review board. The report highlighted several concerns:
- Vendor Lock-In: The agency lacked control over its data as it did not employ Double Key Encryption.
- Lack of End-to-End Encryption: One-to-one Teams calls did not have end-to-end encryption enabled by default.
- Limited Exit Strategy: There was no practical way to switch to an alternative solution later without facing significant challenges.
The New Approach
The on-premises solution became feasible due to the agency's enhanced data center capacity. Eerenberg stated that they will utilize existing licenses where possible to minimize additional costs. They plan to assess alternatives for each function instead of relying solely on one vendor.
Some archive tools will face delays as several records management features were part of the Microsoft 365 package and are not readily available on-premises. The agency is working to find replacements, with updates to be reported in subsequent letters from Eerenberg.
Digital Autonomy and Related Projects
This move aligns with a broader push for digital autonomy within the Dutch government. Other projects include taking over hosting of the new VAT system from suppliers and accelerating the domestic VAT rollout.
Microsoft declined to comment on this matter. Secretary Eerenberg was scheduled to discuss these plans with MPs on October 7th.
The Netherlands is also developing its Linux desktop and joining other European initiatives, such as Airbus migrating critical apps to a French cloud and Brussels implementing stricter tech rules for AWS and Azure.