Thunderbird expands Exchange support

Contents

Thunderbird has released public roadmaps for all its platforms for the first time. They cover the desktop version, the Android app, the upcoming iOS app, and planned pro services. Key initiatives for 2026 include expanded Exchange support, a deep architectural overhaul of the Android app, and initial IMAP support for iOS.

As the Thunderbird team explained in its blog, the roadmaps are not intended to be wish lists but rather a realistic plan of direction for the current year. The descriptions are deliberately written in simple, non-technical language to make them accessible to non-developers. The team reviews progress in quarterly internal reviews and communicates changes via the tb-planning mailing list. Community input is incorporated into planning in the long term, but according to Thunderbird, there are more ideas than available capacity each year, so the project must prioritize new ideas.

Desktop: Database and Exchange

For the desktop version, the team plans further work on the Panorama database, which users can test for the first time. Thunderbird intends to expand and add new APIs for extension developers so that add-ons can access more components of the email client. The Account Hub is to be completed, activated for first-time users, and supplemented with a customization wizard after the initial account creation.

Exchange support, which has been available since Thunderbird 145, will be further expanded. In the future, the email client will support all Exchange and M365 versions by also being able to handle the Microsoft Graph API. Currently, only EWS is included. Calendar and address book support for Exchange are also planned for this year. The calendar interface will also receive an update.

Android and iOS

At the top of the Android roadmap is the app's re-architecture. The underlying codebase comes from K-9 Mail and is correspondingly old. In addition, the message list and view – the areas where users spend most of their time – will be revised. HTML signatures are also planned.

Unlike the Android version, the iOS app is being developed completely from scratch. The architecture was completed in July 2025, followed by autoconfiguration in September. The team is currently working on the account creation process with autodiscovery and OAuth. IMAP will be supported as the first protocol; JMAP and HTML signatures are planned for later.

Pro Services and Outlook

For Thunderbird Pro services, work is actively underway to complete the send user interface and a view for active sessions, allowing users to view and end their sessions. Further plans include MFA support and the implementation of an idea chosen by the community from the ideas portal. Thunderbird Appointment is to be integrated into the Pro add-on. The add-on itself should also be more easily discoverable in Thunderbird Desktop via system or account add-on mechanisms.

A Thundermail webmail based on JMAP is currently only conceptual, which should initially offer basic folder and message display. The team emphasizes that schedules may change during development.

(fo)