• Community
• Development
• Mobile
• Product

Thunderbird 2025 Review: Building Stronger for the Future

2025 was an exciting year for Thunderbird. Many improvements were shipped throughout the year, from faster updates with a new release cadence, to a modernized codebase for the desktop app. We made big strides on our mobile apps and introduced the upcoming Thunderbird Pro to the world.

As we wrap up the year, a huge thank you to our community and volunteer contributors, and to our donors whose financial support keeps the lights on for the dedicated team working on Thunderbird. Here’s what we accomplished in 2025 and what’s to come in the new year.

A Stronger Core, Built to Last

This year marked the release of Thunderbird 140 “Eclipse”, our latest Extended Support Release. Eclipse was more than a visual refresh. It was a deep clean of Thunderbird’s core, removing long standing technical debt and modernizing large parts of the codebase.

The result is a healthier foundation that allows us to ship improvements more reliably and more often. Features like the new Account Hub, accessibility improvements, and cleaner visual controls are all part of this effort. They may look simple on the surface, but they represent significant behind the scenes progress that sets Thunderbird up for the long term.

Faster Updates, Delivered Monthly

Speaking of faster updates, in 2025 monthly releases became the default for Thunderbird desktop. This was a major shift from our focus on the annual cadence centered around the Extended Support Release.

Moving to monthly releases means new features land sooner, bug fixes arrive faster, and updates feel smoother instead of disruptive. Users no longer have to wait an entire year to benefit from improvements. Thunderbird now evolves continuously while maintaining the stability people expect.

Thunderbird Meets Exchange

One of the most requested features is finally here. Native Microsoft Exchange email support landed in Thunderbird’s monthly release channel with 145.0.

You can now connect Exchange accounts directly without relying on third party add-ons for email. Setup is simpler, syncing is more reliable, and Thunderbird works more naturally in Exchange based environments. Calendar and address book support are still in progress, but native email support marks an important milestone toward broader compatibility.

Mobile Moves Forward

Thunderbird’s mobile story continued to grow in 2025.

On Android, the team refined release processes, improved core experiences, and began breaking larger features into smaller, more frequently delivered updates. At the same time, Thunderbird for iOS took a major step forward with a basic developer testing app available via Apple TestFlight. This marked the first public signal that Thunderbird is officially expanding onto iOS, with active development well underway and headed toward iPhones in 2026.

Introducing Thunderbird Pro

In 2025, we announced Thundermail and Thunderbird Pro, the first ever email service from Thunderbird alongside new cloud based productivity features designed to work seamlessly with the app.

Thunderbird Pro will include:

• Thundermail, an open source email service from Thunderbird
• Appointment, a scheduling tool
• Send, an end to end encrypted file sharing service

These services are built to respect user privacy, remain open source, and offer additional functionality by subscription for those who need it, without compromising the forever free and powerful Thunderbird desktop and mobile apps. Throughout the year, we made significant progress across all three services and launched the Thunderbird Pro website, marking a major step toward early access and testing. The Early Bird beta is set to kick off in the first part of 2026. Catch up on the full details in our latest update and, if you’re not on the waitlist yet, join in.

Looking Ahead to 2026

The work in 2025 set the stage for an even more ambitious year ahead.

In 2026, our desktop plans include updating our decades-old database, expanding Exchange and protocol support, and refreshing the Calendar UI. For Thunderbird Pro, we aim to release the Early Bird beta in the first part of the year. Our plans for Android focus on rearchitecture of old code, quality of life improvements, and a new UI. For iOS, we’re moving closer to an initial beta release with expanded protocol support. Be sure to follow this blog for updates on the desktop and mobile apps and Thunderbird Pro.

Thunderbird is moving faster, reaching more platforms, and building a more complete ecosystem while staying true to our values. Thanks for being part of the journey, and wishing all of you a fantastic 2026.
Thunderbird is moving faster, reaching more platforms, and building a more complete ecosystem while staying true to our values.

Thanks for being part of the journey, and wishing all of you a fantastic 2026!