The Netherlands’ Belastingdienst, Douane and Toeslagen chose an on-premises workplace approach combined with open-source services, according to a letter dated October 5, 2026, from State Secretary for Finance E. Eerenberg. The plan revises the agencies’ planned Microsoft 365 public-cloud rollout and sets out phased service changes. (Dutch House of Representatives record)
NeoTeo’s earlier coverage of the Dutch Microsoft 365 shift reported the change in direction. Eerenberg’s letter spells out which agencies the revised approach covers and how its service phases are scheduled.
What the agencies chose
The plan covers the Belastingdienst, Dutch Customs (Douane) and Benefits (Toeslagen). In this context, on-premises means software running on servers owned or controlled by the Belastingdienst. The letter says expanded data-center capacity helped make that option possible.
The approach combines on-premises hosting with open-source services. It also aims to use as many existing licenses as possible to limit additional investment, so the plan does not describe a complete break from Microsoft.
The planned service schedule
The letter sets out two phases. These are planned changes, not completed deployments.
| Service area | Planned approach | Planned timing |
| Email and calendars | On-premises provision | 2027 |
| Personal storage and collaboration | European open-source solutions | Later in 2027 and in 2028 |
Information and archive functions still under assessment
Some information-management and archive-management functions included in Microsoft 365 are not available in the on-premises approach. The administration is assessing what it needs to address that gap and says it will return to the issue in a later status letter.
