Netherlands Ditches Microsoft 365 in Favor of Open Source Shift

The Dutch government has made a significant decision by discontinuing its planned rollout of Microsoft 365 for its Tax and Customs Administration. This move is part of a broader strategy to enhance digital sovereignty through open-source alternatives, reflecting a growing trend across Europe.

Rationale Behind the Decision

At the recent Open Source Summit Europe, the Linux Foundation presented findings from their 2026 State of Open Source in Europe report. The research highlighted that an impressive 94% of EU organizations prioritize digital sovereignty, with 61% attributing it a high level of importance. Thierry Carrez, General Manager of Linux Foundation Europe, emphasized the urgent need for European entities to secure their digital infrastructure.

The Dutch Tax and Customs Administration had initially aimed to complete its transition to Microsoft 365 by the end of 2026, and approximately 5,000 employees had already made the switch. Nonetheless, the Dutch Advisory Council on ICT Assessment issued a recommendation in June to halt the rollout due to various concerns.

Open Source as a Solution

The assessment raised issues about information security, data processing capabilities, and the protection of confidential information. The Dutch authorities were particularly apprehensive about transmitting sensitive documents through American servers, which could potentially compromise data confidentiality.

Another central concern was the encryption architecture associated with Microsoft 365. The proposed standard encryption did not meet the requirements set by the government; instead, they preferred Double Key Encryption, which grants more control over sensitive data. Additionally, the lack of default end-to-end encryption for Teams calls was a significant drawback.

Future Plans for Open Source Adoption

As the Dutch government charts a new course, they will continue to utilize existing Microsoft software such as Outlook for email and calendar services in the short term. However, plans are underway to develop open-source solutions for personal storage and collaboration tools starting in 2027. State Secretary for Finance, Eelco Eerenberg, outlined in a letter to Parliament that by 2028, the administration seeks to have fully operational European open-source solutions.

While specifics remain unconfirmed, the current focus is on the development of the Digital Autonomous Work Environment for Government (DAWO). This initiative aims to replace the existing Windows desktop environment with NixOS, a Dutch Linux distribution.

The government is also discussing the potential integration of various European open-source solutions like France’s La Suite and Germany’s openDesk, while considering a customized system called MijnBureau. This self-hosted solution would incorporate multiple open-source projects, including Nextcloud for storage, Collabora for document management, Element for messaging, and OpenProject for project management.

Despite the ambiguity surrounding precise implementations, the Dutch Tax and Customs Administration's shift from Microsoft signifies a substantial movement towards creating a more secure and independently controlled digital environment.