Something to look forward to: After relaunching the Thunderbird project in 2020 by establishing the new MZLA subsidiary, the Mozilla Foundation is busy improving its email client software. The organization has now unveiled some of the most interesting changes expected in the coming months.
Last year was a "fantastic" one for Thunderbird, according to Mozilla. However, the best is yet to come. The "Supernova" upgrade (Thunderbird 115) was the most significant milestone of the past year, introducing a new codebase (once again based on the Firefox project) to further modernize one of the most popular (and open-source) email clients out there.
Despite the controversial reception of Supernova's rebuilt interface, MZLA developers are diligently working to add more flexibility, reliability, and customizable options to Thunderbird. The email client aims to accommodate different needs and workflows, as Mozilla states. The project's revitalization is now symbolized by a new logo created by Jon Hicks, the designer of the original Firefox and Thunderbird logos.
One of the primary changes Thunderbird developers are currently working on is support for Microsoft Exchange, the popular mail server and calendaring platform designed to run exclusively on Windows Server operating systems. Mozilla acknowledges that Thunderbird users are "expecting" this functionality, and some "exploratory work" has already been done on that front.
The Thunderbird codebase can now utilize the Rust programming language, seemingly a prerequisite for both improving the existing code architecture and introducing Exchange support. Native support for the Exchange protocol is a "complex topic," warns Mozilla, but at least it is now officially on the program's roadmap.
According to Bugzilla's relevant bug tracking thread, Mozilla plans to "fully support" Microsoft Exchange, including user authentication, email, calendar, and contacts. Thunderbird aims to provide support for Exchange through the EWS (Exchange Web Services) protocol, an alternative to the standard Microsoft MAPI protocol.
EWS is a deprecated feature that will be abandoned by Exchange Online on October 1, 2026. However, developers argue that the protocol remains the best way to enable support for both Exchange Online and on-premise custom Exchange Server installations. Microsoft's new Graph API for cloud access has been considered and "may be" revisited in the future.
In addition to implementing Exchange support, the Thunderbird team is focusing on improving communication with the community and introducing previously announced features such as Sync and Account Hub. Marketing efforts will also be increased, featuring new tutorials, video guides, and other productivity-focused content.