Germany's Schleswig-Holstein Completes Migration to Open Source Email

Summary

European nations have generally been more progressive in adopting open source solutions for government operations. Sure, regressive proposals like the EU Chat Control bill make headlines, but there's genuine progress happening too.The German state of Schleswig-Holstein is back in the news for its open source efforts. This time, it's their email system that's undergone a complete transformation.Microsoft Booted Out, AgainSchleswig-Holstein has successfully migrated (in Deutsch) its entire state administration email system from Microsoft Exchange and Outlook to open source alternatives, Open-Xchange and Thunderbird. The German state completed the transition on October 2, 2025, after a six-month process.The migration affected around 30,000 employees across various government departments. This includes the State Chancellery, ministries, judiciary, state police, and other state authorities. Over 40,000 mailboxes containing more than 100 million emails and calendar entries were moved to the new system.The state has adopted Open-Xchange as its email server solution and Thunderbird as the email client.Of course, the transition wasn't without challenges. Digitization Minister Dirk Schrödter previously acknowledged problems during migration to open source software, including downtime and delays in email traffic. Despite these hurdles, this particular move has now been completed successfully.Plus, this switch fits into Schleswig-Holstein's broader open source strategy that has been in development for several years. The state began rolling out LibreOffice as its standard office software last year, gradually replacing Microsoft Office across all state computers.Dirk also emphasized that:We are real pioneers. We can't fall back on the experience of others –, there is hardly a comparable project of this magnitude anywhere in the world. In future, we will be able to use our experience from data analysis to monitoring in the data centre to help others and support them when they emba...