Dutch tax agency scraps its Microsoft 365 cloud rollout over encryption and exit terms

For a tax employee, the near-term change is smaller than the headline. In 2027 mail and calendar move on-premises, and ZDNet reports that the on-premises environment will still run Microsoft software, including Outlook ^[15]. The open-source part covers personal storage and collaboration. It does not replace Word, Excel or PowerPoint ^[15].

State Secretary for Finance Eelco Eerenberg set the dates in a letter to Parliament. He wrote: "In 2027, the provision for mail and calendar will be realized on-premises. Later in 2027 and 2028, European open-source solutions for personal storage and collaboration will follow." ^[8] The original plan was to switch in 2025 and finish by the end of 2026 ^[5].

The advisory council's objections were specific. It found the chosen public-cloud design fell short on "information security, information processing and future-proofing" ^[9]. Its concerns included confidential documents passing through American servers instead of the government networks used before ^[10]. Under the selected configuration, end-to-end encryption would not have been on by default for one-to-one Teams calls and would have been unavailable for group calls ^[12]. The assessment also named vendor lock-in, reduced flexibility, sovereignty concerns and the absence of an adequate exit strategy as showstoppers ^[14]. ZDNet notes that the criticisms target this deployment design. They do not claim every Microsoft 365 configuration has the same disadvantages ^[13].

Teams tend to tell themselves that a high sovereignty score on a survey turns into cancelled contracts. The Linux Foundation, a nonprofit that advocates for open source ^[7], reported that 94% of EU organizations call digital sovereignty important and 61% call it very important ^[6]. Reading the 61% as a subset of the 94%, 33 points call it important without calling it very important ^[19]. The Dutch file shows something narrower: encryption settings, call-security defaults and an inadequate exit plan. ZDNet's writer adds his own view that the Dutch "don't trust American companies under the current US government" ^[20].

We'd tell European buyers to write the exit plan and settle who holds the encryption keys before they shortlist a non-US alternative. The tradeoff is time spent on a plan with no destination. The Dutch have not chosen any open-source programs or stacks ^[16], and other Dutch agencies have only started developing DAWO, the Digitaal Autonome Werkomgeving Overheid ^[17].

Two checks sort each workload: whether the customer or the vendor holds the encryption keys, and whether a written exit plan exists. Vendor keys with no exit plan is the Dutch design, and the council stopped it. Customer keys with a written exit plan answers two of the council's named objections, though in our view it leaves the American-servers concern open. The two mixed cells tell you which fix to buy first. Workloads in the first cell need a date by which they move or change; workloads in the last can wait for a replacement to exist.