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In April of this year we announced Thunderbird Pro, additional subscription services from Thunderbird meant to help you get more done with the app you already use and love. These services include a first ever email service from Thunderbird, called Thundermail. They also include Appointment, for scheduling meetings and appointments and Send, an end-to-end encrypted filesharing tool. Each of these services are open source, repositories are linked down below.

Thunderbird Pro services are being built as part of the broader Thunderbird product ecosystem. These services are enhancements to the current Thunderbird application experience. They are optional, designed to enhance productivity for users who need features like scheduling, file sharing and email hosting, without relying on the alternate platforms. For users who opt in, the goal is for these services to be smoothly integrated into the Thunderbird app, providing a natural extension of the familiar experience they already enjoy, enhanced with additional capabilities they may be looking for. For updates on Thunderbird Pro development and beta access availability, sign up for the mailing list at thundermail.com. 

Progress So Far

Thundermail

Development has been moving steadily forward and community interest in Thundermail has been strong. The upcoming email hosting service from Thunderbird will support IMAP, SMTP and JMAP out of the box, making it compatible with the Thunderbird app and many other email clients. If you have your own domain, you’ll be able to bring it in and host it with us. Alternatively, grab an email address provided by Thunderbird with your choice of @thundermail.com or @tb.pro as the domains.  The servers hosting Thundermail will initially be located in Germany with more countries to follow in the future. Thunderbird’s investment in offering an email service reflects our broader goal of strengthening support for open standards and giving users the option to keep their entire email experience within Thunderbird. 

Thunderbird Appointment (Repo)

We originally developed the scheduling tool as a standalone web app. On the current roadmap, however, we’re tightly integrating Appointment into the Thunderbird app through the compose window, allowing users to insert scheduling links without leaving the email workflow. It will be easy for organizations and individuals to self-host, fork and adapt the tool to their own needs. The future is for Appointment to support multiple meeting types, like Zoom calls, phone meetings, or in-person coffee chats. Each of these will have its own settings and scheduling rules.

One of the most requested future features is group scheduling, which would allow multiple team members to offer shared availability via a single link. The current calendar protocols don’t fully support this flow, however Thunderbird is participating in discussions around open standards like VPOLL to help move things forward. Usability studies are helping refine the MVP and community feedback is shaping the roadmap.

Thunderbird Send (Repo)

A secure, end-to-end encrypted file sharing tool, built on Thunderbird app’s existing Filelink feature. It supports large file transfers directly from the email client. This allows users to bypass platforms like Google Drive or OneDrive. Pro users will receive 500 GB of storage to start, with no individual file size limit, only constrained by their total quota. We’re planning support for chunked uploads and encryption to ensure reliability and data protection. We’ll deliver Send as a system add-on which lets the team push updates faster. This also avoids locking new capabilities behind major Thunderbird release cycles.

All Thunderbird Pro tools are open source and self-hostable. For users who prefer to run their own infrastructure or work in regulated environments, both Send and Appointment can be deployed independently. Thunderbird will continue to support these users with documentation and open APIs.

A Look Ahead

Thunderbird is exploring additional Pro features beyond the current lineup. While we’ve made no commitments yet, there is strong interest in adding markdown based Notes functionality, especially as lightweight personal knowledge management becomes more popular. Heavier lifts like collaborative docs or spreadsheets may follow, depending on adoption and sustainability.

Another worthy mention: a fourth, previously announced service called Assist, which will eventually enable users to take advantage of AI features in their day-to-day email tasks, is still in the research and development phase. It will not be part of the initial lineup of services. This initiative is a bigger undertaking as we ensure we get it right for user privacy and make sure the features included are actually things our users want. More to come on this as the project progresses.

To improve transparency and invite community collaboration, Thunderbird is also preparing a public roadmap covering desktop, mobile and Pro services. We’re developing the roadmap in collaboration with the Thunderbird Council. Our goal is to encourage participation from contributors and users alike.

Free vs Paid

Adding these additional subscription services will never compromise the features, stability or functionality our users are accustomed to in the free Thunderbird desktop and mobile applications. These services come with real costs, especially storage and bandwidth. Charging for them helps ensure that users who benefit from these tools help cover their cost, instead of donors footing the bill. 

Thunderbird Pro is a completely optional suite of (open source) services designed to provide additional productivity capabilities to the Thunderbird app and never to replace them. The current Thunderbird desktop and mobile applications are, and always will be, free. They will still heavily rely on ongoing donations for both development and independence.

If you haven’t already, join our waiting list to be one of the early beta testers for Thunderbird Pro. While we don’t have a specific timeline just yet, we will be sharing ongoing updates as development progresses.

—

Ryan Sipes
Managing Director, Product
Mozilla Thunderbird

The post Thunderbird Pro August 2025 Update appeared first on The Thunderbird Blog.

Hello again from the Thunderbird development team! As the northern hemisphere rolls into late summer and the last of the vacation photos trickle into our chat channels, the team is balancing maintenance sprints with ongoing feature-related projects. Whether you’re basking in the sun or bundled up for a southern winter, we’ve got plenty to share about what’s been happening behind the scenes, and what’s coming next.

Exchange support

It’s been a whirlwind of progress since our last update and with the expanded team collaborating regularly. It has felt like we’ve hit our stride and the finish line is in sight. Driven by a dramatic increase in automated test coverage, the team has been able to detect gaps and edge cases to help improve many areas of the existing code, and close out a good number of bugs.

As we ready the feature set for wider release, we’ve taken the opportunity to revisit the backlog and feel confident enough with our pace to prioritize a few features and address them sooner than originally planned.

The July roadmap worked out very well, with our planned features landing and a number of bonus items also complete:

• Automated test coverage
• Message filtering
• Setting as Junk/Not Junk
• Remote content display/blocking
• Callback modernization/simplification
• Propagation of certificate and connection errors
• Archiving
• Saving Drafts
• Back-off handling

Items we’ve prioritized for the next few weeks are:

• Undo/Redo operations for move/copy/delete
• Status Bar feedback messaging
• Bug backlog

Keep track of feature delivery here.

Account Hub

A few users have reported issues following end user adoption of this feature, so we’re addressing these while finalizing Account Hub for Address Book items, such as LDAP configuration. The team is also planning the implementation of telemetry which will help us determine areas for improvement in this important part of the application.

Global Message Database [Panorama]

The team has been focused on Exchange implementation and larger scale refactoring which isn’t directly tied to this project, so no updates to note here. The next time I write will be during a work week that has been dedicated to “Conversation View”, which is one of the key drivers for our database overhaul. Stay tuned for updates and decisions coming out of that collaboration.

To follow their progress, take a look at the meta bug dependency tree. The team also maintains documentation in Sourcedocs which are visible here.

Maintenance, Recent Features and Fixes

August is set aside as a focus for maintenance, with half our team dedicated to inglorious yet important items from our roadmap. In addition to these items, we’ve had help from the development community to deliver a variety of improvements over the past month:

• Various newsgroup fixes
• Another pile of port bugs to adapt Thunderbird to upstream changes
• Implementation of standard colours throughout the application. [meta bug]
• Modernization of module inclusion. [meta bug]
• and many more which are listed in release notes for beta.

If you would like to see new features as they land, and help us squash some early bugs, you can try running daily and check the pushlog to see what has recently landed. This assistance is immensely helpful for catching problems early.

—

Toby Pilling

Senior Manager, Desktop Engineering

The post Thunderbird Monthly Development Digest – July 2025 appeared first on The Thunderbird Blog.

David Allen’s “Getting Thing Done” (GTD) system has been around for longer than Thunderbird! First published in a book of the same name in 2001, this approach to productivity is focused on freeing your brain from chaos, giving it “focus, clarity, and confidence” for creativity and new ideas. As I’m also a fan of freedom from chaos, I decided to dive back into our productivity blogs and highlight how to use tags and keyboard shortcuts to use GTD in Thunderbird.

Five Steps to Get Things Done

To start, let’s summarize the GTD system, for anyone who might not be familiar. GTD uses five key steps to go from unorganized to unstoppable, whether in your inbox or elsewhere: Capture, Clarify, Organize, Reflect, and Engage.

Let’s think about these steps in terms of managing your inbox! First, Capturing involves collecting the things that have your attention. In other instances, this could mean brainstorming a to-do list. For email, this means your inbox. Clarifying entails taking those items and figuring out what they mean. For the Getting Things Done system, you need to figure out if you can act on something (for example, an email) or not. If it’s not actionable, where does it needs to go Is this reference? Is this on hold for some reason? Or can it just go in the trash?

Once this clarifying is done, it’s time to Organize, aka putting the things that have your attention or reminders of them in a place you can act on, whether that’s now or later. Reflecting isn’t a one-time step, but something you do consistently to fine-tune your system and make sure it’s still working for you.

All of these steps make the last step, Engaging, possible. You have a system you can trust, honed through reflection. Your inbox management system is like a starship where everything and everyone is working together, efficiently and effectively. This frees up your brain so your brain can soar through a cosmos of deep, interesting, meaningful work. Maybe while drinking a cup of tea, Earl Grey, hot.

Using Tags and Keyboard Shortcuts to Clarify and Organize Your Inbox

Adapting the GTD system to your Thunderbird inbox takes advantages of two features I am coming to love: labels and keyboard shortcuts.

I’m going to suggest three initial labels, and a few possibilities for labels for non-actionable emails, and walk you through how to set up the labels and use the keyboard shortcuts to apply them – with screenshots!

First, go into Settings > General > Tags to create/adjust your tags. The four example tags we set are “Do Now,” “Do,” “Waiting For,” and “Later.”

Wait, why have a “Do Now” and “Do” tag? This tip came from Henk Postma’s blog, who gave me a lot of inspiration. “Do Now” is urgent, and it needs doing without delay. “Do” doesn’t have this urgency, but the email is actionable.

The “Waiting For” label means there’s something you need to act on this email. Maybe it’s more information, or permission. This label can keep hold those emails until you’re ready. The “Later” tag is a bit of a catch-all. Like reference information, or things you’re interested in but can’t pursue yet. Maybe you want to break down your “Later” labels. The choice is yours!

Now that we have our labels set up, and associated with a number, we’re ready to start organizing. Once a message comes in, click the number for the tag you want. If you accidentally press the wrong number, don’t worry! Just press ‘0’ to clear whatever label you applied.

And that’s it! Well, except putting your system into practice, and David Allen has some further advice on using GTD in your inbox. If you have any tips on how you make your email organization a habit and not an afterthought, I’d love to hear them! As always, if there’s a productivity topic you’d like me to explore, let me know in the comments!

The post Engage Your Inbox with ‘Getting Things Done’ appeared first on The Thunderbird Blog.

We’re launching a brand new series that will highlight features and improvements with Thunderbird 141.0 – your front row ticket to Thunderbird’s monthly enhancements! (No more waiting in the wings so to speak). Learn what’s new, why it matters, and how it’ll transform your inbox experience.

In March, we introduced a new monthly Release channel and swapped it as the default option on the Thunderbird.net downloads page.

As a quick refresher, Thunderbird now offers two core release channel options:

1. Release Channel: Updated monthly with new features, performance boosts, and bug fixes as they land.
2. ESR (Extended Support Release): Receives all of the above in one major annual update, focusing on stability, with point security and stability patches in between.

While both versions are equally stable, the Release channel provides faster access to cutting-edge tools and optimizations, while the ESR channel may provide more stability when using add-ons with Thunderbird.

Feedback on the Release channel has been overwhelmingly positive, with many users transitioning from ESR. To join them:

• Visit the Release download portal: Thunderbird Release Page.
• Explore detailed comparisons and migration guides.

Now that we’ve gotten the formalities out of the way, let’s jump in to what’s new in 141.0!

New Features

Warning for Expiring PGP Keys

Thunderbird loves PGP like cats adore cardboard boxes! We prioritize user trust by making end-to-end encrypted email simple for everyone, from newcomers to experienced users. To help you get started or refresh your knowledge, our team and volunteers have written an excellent introduction to the topic, as well as a How-to and FAQ.

Key expiration serves as a security safeguard, requiring proactive renewal procedures that reinforce operational encryption competencies.

What changed:

• Your warning light is lit: If your public key expires in 31 days, Thunderbird now flashes a red alert in the compose window. No post-expiry panic!

Why it matters:

• Safety net: A key that auto-expires nudges you to refresh it.
• Piece of mind: Before Thunderbird told you after-the-fact your key died. Now? Your inbox is proactive.

Archive from OS Notifications

The improvements to native notifications keep coming. Now, in addition to deleting a message, marking it as spam, or starring it, you can archive a message directly from your operating system’s notifications. 

By default, the notifications you see include “Mark as Read” and “Delete”, however they can be customized further by going to Thunderbird Settings → General→ Incoming Mails and clicking on Customize.

Here you can select the information you want to see in your notification, as well as the actions you’d like to perform with it.

What changed:

• New mail notifications have added the ‘Archive’ action.

Why it matters:

• No need to go into the Thunderbird app to archive an incoming email now. More actions in notifications give you time to do the things you want, instead of managing your inbox.

Bug Fixes

Prioritize Link Hover URL in Status Bar

Thunderbird includes numerous features to protect you from suspicious mail and bad actors. One of these tools involves checking the URL of a link by hovering your mouse over the link text. The status bar would display the link URL, but it could be overwritten in fractions of a second by “Downloading message” and “Opening folder” messages. We’ve fixed this, and now the URL you’re hovering over will get priority in the status bar.

What changed:

• Hovering over a link in an email will display it in the status bar without being immediately overwritten by other messages.

Why it matters:

• Knowing where an email wants to send you is a major security boost, especially with the widespread threat of phishing emails.

Dots, Dashes, and Advanced Address Book Search

Three months ago, a community member noted that while the CardBook add-on could find phone numbers that used dots for separators, the Advanced Address Book Search in Thunderbird could not. Since we want users to be able to find contacts, and use the phone number formatting they want as well, we’ve built this ability into Thunderbird.

What changed:

• The advanced address book in Thunderbird now recognizes phone numbers that use dots for separators.

Why it matters:

• Saves time: Finds contacts faster and more accurately, no matter their format or storage location, eliminating need for manual cleanup or repeat searches.

Performance Improvements

Message List Scroll

To address message list scrolling performance, we adjusted how new rows are rendered but inadvertently introduced display delays. We’re reverting to the original row-handling method to properly assess performance impact before considering this change for Extended Support Release adoption. This allows precise measurement of optimizations against potential trade-offs, ensuring reliable performance in production environments.

What changed:

• Reverting back to the previous method for how rows are updated.

Why it matters:

• To accurately measure how the update affects scrolling performance before considering inclusion in an ESR.

The post Monthly Release 141 Recap appeared first on The Thunderbird Blog.

For the past few months, we’ve been talking about our roadmaps and development and answering community questions in a video and podcast series we call “State of the Thunder.” We’ve decided, after your feedback, to also cover them in a blog, for those who don’t have time to watch or listen to the entire session.

This session is focused on answering inquiries from the community, and we’ve got the questions and summaries of the answers (with helpful links to resources we mentioned)! This series runs every two weeks, and we’ll be creating blogs from here on in. If you have any questions you’d like answered, please feel free to include them in the comments!

Supporting and Sustaining FOSS Projects We Use

Question: As we move toward having more traditionally commercial offerings with services that are built on top of other projects, what is our plan in helping those projects’ maintenance (and financial) sustainability? If we find a good model, can we imagine extending it to our apps, too?

Answer: Right now, the only project we’re using to help build Thunderbird Pro is Stalwart, and we’ll have more details on how we’re using it soon. But we absolutely want to make sure the project gets financial support from us to support its sustainability and well-being. We want to play nice!

Appointment and Assist are from scratch, and Send is from old Firefox code, and so there isn’t another project to support with those. But to go back to a point Ryan Sipes has frequently made, while people can use all of these tools for free by self-hosting, they can subscribe as a way of both simplifying their usage and making sure these projects are supported for regular maintenance and a long life.

Future UI Settings Plans

Question: The interface is difficult to customize but more importantly is difficult to discover all the options available because they’re scattered around settings, account settings, top menu bar, context menus, etc. 140 Introduced the Appearance section in the settings, any plans to continue this effort with some more drastic restructuring of the UI?

Answer: Yes, we do have plans! We know the existing UI isn’t the most welcoming, since it is so powerful and we don’t want to overwhelm users with every option they can configure. We have a roadmap that’s almost ready to share that involves restructuring Account Settings. Right now, individual settings are very scattered, and we want to group things together into related sections that can all be changed at the same time. We want to simplify discoverability to make it easier to customize Thunderbird without digging into the config panel.

Account Setup and Manual Configuration

Question: Using manual configuration during email setup has become more difficult with time with the prioritization of email autoconfiguration.

Answer: Unfortunately, manual setup has confused a lot of casual users, which is why we’ve prioritized autodiscovery and autosetup. We’ve done a lot of exploration and testing with our Design team, and in turn they’ve done a lot of discussion and testing with our community. You can see some of these conversations in our UX mailing list. And even if you have to start the process, there is a link in it to edit the configuration manually. Ultimately, we have to have a balance between less technical and more technical users, and to be as usable and approachable as we can to the former.

Balancing Complexity and Simplicity

Question: Thunderbird is powerful with a lot of options but it should have more. Any plans to integrate ImportExportTools  (and other add-ons) and add more functionalities?

Answer: Thunderbird’s Add-ons are often meant for users who like more complexity! When we tackle this question, there’s two issues that come to mind. First, several developers get financial support from their users, and we want to be mindful of that. Second is the eternal question of how many features are too many features? We already have this issue in feedback between “Thunderbird doesn’t have enough features” and “Thunderbird is too complicated!” Every feature we add gives us more technical debt. If we bring an add-on into core, we can support it for the long term.

We think this question may also come from the fact that Add-ons often “break” with each ESR release. But we’re trying to find ways to support developers to use the API to increase compatibility. We’re also considering how we can financially support Add-on developers to help them maintain their apps. Our core developers are pressed for time, and so we’re beyond grateful to the Add-on developers who can make Thunderbird stronger and more specialized than we could on our own!

Benefits of the New Monthly Release Channel

Question: Is the new Release channel with monthly versions working properly and bringing any benefits?

Answer: Yes, on both counts! Right now, we have 10 to 20 percent of Thunderbird desktop users on the Release channel. While we don’t have hard numbers for the benefits YET, we’d love to get some numbers on improvements in bug reactivity and other indicators. We noticed this year’s ESR had far fewer bugs, which probably owed to Release users testing new features. While we’ve always had Beta users, we have so many more people on Release. So if something went wrong, we could fix it, let it “ride the train,” and have the fix in the next version.

And our developers have stopped wondering when our features will make it to users! Things will be in users’ hands in a month, versus nearly a year for some features.

JMAP Support in Thunderbird

Question: Any plans on supporting JMAP?

Answer: 100% yes. Though JMAP is still something of a niche protocol, with doesn’t yet have widespread support from major providers. But now, with Thundermail we’ll be our own provider, and it will come with JMAP. Also, with the upcoming iOS app, it will be easy to add support for JMAP. First, we’re making the app from scratch so we have no technical debt. Second, we can do things properly from the start and be protocol agnostic.

Also, we’ve taken several lessons from our Exchange implementation, namely how to implement a new protocol properly. This will help us add support for JMAP faster.

Maintaining Backups in Thunderbird

Question: I have used Thunderbird since its first release and I always wondered how to properly and safely maintain backups of local emails. No matter how much I hate Outlook it offers built-in backup archives of .pst files that can be moved to other installations. The closest thing in Thunderbird is to copy the entire profile folder, but that comes with many more unpredictable outcomes.

I might be asking for something uncommon but I manage many projects with a very heavy communication flow between multiple clients, and  when the project is completed I like to export the project folder with all the messages into a single PST file and create a couple of back-ups for safety, so no matter if my email server has problems, or the emails on my server and computer are accidentally deleted, I have that folder back-up as a single file which I can import into a new installation.

Answer: We’d love for anyone with this question to come talk to us about how to improve our Import/Export tools. Unfortunately, there’s no universal email archive format, and a major issue is that Outlook’s backup files are in a proprietary format. We’ve rebuilt the Import/Export UI and done a bit on the backend. Alas, this is all we’ve had time for.

So, if you’d like to help us tackle this problem, come chat with us! You can find us on Matrix and in the Developers and Planning mailing lists. We think there’s definitely room for a standard around email backups.

Watch the Video (also available on TILvids)

Listen to the Podcast

The post State of the Thunder: Answering Community Questions! appeared first on The Thunderbird Blog.

Community First

Thunderbird is (and has always been) powered by the people. The project exists because of the amazing community of passionate code contributors, bug-bashers, content creators, and all-around wonderful humans who have stood behind it and worked to support and maintain it over the years.

And as the Thunderbird community grows, we want to ensure that we [the team supporting you] grow alongside you, so that we can continue to collaborate and build effectively and efficiently together. 

That’s why we’re thrilled to announce a refreshed and growing Thunderbird Community Team here at MZLA! Expect a little more structure, a lot more collaboration, and an open invitation to our users and contributors to join us and help shape what comes next.

Meet the Team

Whether you’re filing your first bug, searching for support, writing documentation, or just dropping into Matrix to say hi, this is the team working hard behind the scenes to make sure your experience is productive, constructive, and superconductive:

Michael Ellis | Manager of Community Programs

Hey there! I’m Michael, and I’m joining the Thunderbird family as Manager of Community Programs to help grow and support our awesome community. I’ll be working on programs that help improve contributor pathways and make it easier for more people to get involved in the work we do and the decisions we make on a day-to-day basis.

I come from a background of managing developer communities and running large-scale programs at organizations like Mozilla, Ionic, and NXP Semiconductors. I believe open-source communities are strongest when they’re welcoming, engaging, and well-supported. I like gifs and memes very much. 

I look forward to seeing you in the Thunderbird community and saying hello to one another on Matrix!  

Until then, Keep on Rocking the Free Web!

Wayne Mery | Senior Community Manager

Greetings everyone.  Wayne here, also known as wsmwk.  I have used open source for forty years, been a user of and contributor to Thunderbird for twenty years, and am a founding member of the Thunderbird Council, and have run several of the council elections. 

I love to mentor and connect to our community members who assist Thunderbird users in Reddit, Connect, matrix (chat), bugzilla, github, topicbox forums, Thunderbird support in SUMO (SUpport MOzilla), and other venues.  And I help manage these venues and assist users, to bring the concerns of the user community to developers.  I also assist in developing content for users (including knowledge base articles in SUMO) and assist in our general communications with users.  

There are many ways you can participate in small ways or large, including through praise or constructive feedback through the venues listed above and those listed on our participate web page – I encourage you to do so at your convenience. And I look forward to connecting with you soon. 

Heather Ellsworth | Senior Developer Relations Engineer

Hi everyone! *waves*

I’ve been part of the Thunderbird family for nearly two years, working with the awesome Desktop team. Now, I’m thrilled to be joining the Community team, led by Michael, where I’ll be focusing on initiatives to support and grow our amazing contributor community.

My work will include creating helpful video content to make it easier for folks to get started, as well as improving our technical documentation at source-docs.thunderbird.net and developer.thunderbird.net.

If you’re interested in contributing or need help getting started, don’t hesitate to reach out to me on Matrix — I’d love to chat!

What’s the Road Ahead?

Community is at the heart of everything Thunderbird does. As our product continues to evolve and improve, we want our community experience to keep pace with that growth. This means not only working to keep Thunderbird open, but striving towards better contributor pathways, clearer communication, and more opportunities to participate.

We’re here to listen, collaborate, and help you succeed. You can expect to see more initiatives, experiments, and outreach from us soon, but you don’t have to wait till then to weigh in.

Have thoughts or suggestions? Drop a comment below to share them directly, or visit our Connect thread to see what others are saying and add your own ideas there. Together, we can help shape the future of the Thunderbird community and product.

After all, Thunderbird is powered by the people, & that includes you.

The post Welcoming New Faces to the Thunderbird Community Team appeared first on The Thunderbird Blog.

Welcome back to another edition of the Community Office Hours! This month, we’re taking a closer look at Thunderbird 140.0 ESR “Eclipse,” our latest Extended Support Release! Sr. Manager of Desktop Engineering Toby Pilling (who so helpfully provides the Thunderbird Monthly Development Digest) is walking us through the latest Thunderbird. He’ll let us know what’s in, what’s out, and why you should give the new monthly Release channel a try. We’re also introducing a new member of the Thunderbird Team, Manager of Community Programs Michael Ellis.

Michael (and the Thunderbird team!) are here to listen, collaborate, and help you succeed. You can expect to see more initiatives, experiments, and outreach from us soon, but you don’t have to wait till then to weigh in. Have thoughts or suggestions on how to improve the community? Drop a comment below to share them directly, or visit our Connect thread to see what others are saying and add your own ideas there. Together, we can help shape the future of the Thunderbird community and product.

Next month, we’ll be talking with Product Design Rebecca Taylor and Associate Designer Solange Valverde to talk about our team’s recent efforts to make Thunderbird more accessible. This not only involves seeing where we’re doing well, but finding where we’re falling short. It’s been a while since we’ve talked about Accessibility here, and we’re excited to continue the conversation. If you have questions about Accessibility in either the desktop or Android app you’d like us to ask our guests, please leave them as a comment below!

July Office Hours: Thunderbird 140.0 ESR “Eclipse”

As Toby shows us in his introduction, the major theme of Thunderbird 140.0 ESR “Eclipse” is stability. We took lessons from last year’s ESR, when we introduced code to 128.0 that was a little harder to test than expected given when it landed. We’re also waiting on some major changes in the works, namely the refreshed Calendar UI and the database backend rewrite. This was, every feature that made it to this year’s ESR was fully baked.

What’s In

And there’s a lot of features to discuss! Toby walks through what’s new in 140.0, starting with a trio of visual improvements. Thunderbird now adapts the message window to dark mode, and provides a toggle to switch dark mode off in case of styling issues. In the new Appearance Settings, users can globally take control of their message list, toggling between Cards and Table View, Threaded and Unthreaded, and Grouped by Sort across all their accounts. This feature also allows switching Cards View between a 2 and 3 row preview, and to propagate default sorting orders to all folders. Finally, a community-powered and staff-supported feature allows users to reorder user-created folders by manually dragging and dropping them.

140.0 ESR Also introduces the Account Hub, which we covered in a previous Office Hours! You’ll see this when you add a second account, and it will seamlessly walk you through setting up not only your email, but connected address books and calendars.

To help maximize your time and minimize your clicks, Thunderbird now uses Native Notifications for Linux, Mac, and Windows. While for now you can delete messages and mark them as read directly from notifications, we have more actions up our sleeve, coming soon to the monthly Release channel!

Finally, we close out our new features. Experimental Exchange Support, which can be enabled via preference, introduces native Exchange email support to desktop Thunderbird. Though for a fully supported experience, we encourage you to switch to the monthly Release channel, where more Exchange improvements are coming. Export for Mobile allows you to generate a QR code to import your account configurations and credentials into the Thunderbird Android app. And Horizontal Scroll for Table View allows you to scroll the message list horizontally and read complex tabular data more like a spreadsheet.

What’s Out

But for everything we put in to 140.0 ESR, we had to leave some things out. Experimental Exchange Support only includes email, not calendar or address books. We also don’t yet support Graph API. Additionally, 140.0 ESR doesn’t include a new UI for Tasks, Chat, or Settings. Account Hub won’t be enabled for first-time user experiences in ESR, though this will be coming to monthly Release, as will the new Account Hub for Address Books.

Try the Monthly Release Channel

While we’re excited and proud to introduce Thunderbird 140.0 ESR “Eclipse,” we also hope you’ll try out new monthly Release channel. Read more about it and learn how you can get new features faster in our announcement.

Watch, Read, and Get Involved

Thanks for reading, and as always, you can learn more by watching the video (with handy chapter markers, if you just want to hear about your favorite new feature) and reading the presentation slides. If you’re looking to get involved with the community, from QA to support to helping develop new features, check out our “Get Involved” page on our website. You can also check out the specific resources below! See you all next month.

VIDEO (Also on Peertube):

Slides:

Resources:

• Thunderbird UX Mailing List: https://thunderbird.topicbox.com/groups/ux
• Interested in the Thunderbird Accessibility Committee? Email laurel@thunderbird.net
• Suggest new features: https://connect.mozilla.org
• Account Hub Office Hours blog: https://blog.thunderbird.net/2025/04/video-the-new-account-hub/
• Manual Folder Sort Bug (and Community Development): https://bugzilla.mozilla.org/show_bug.cgi?id=1846550
• Exchange Support Wiki: https://wiki.mozilla.org/Thunderbird:Exchange
• Get Involved With Exchange: email heather@thunderbird.net
• Thunderbird + Rust Office Hours Playlist: https://www.youtube.com/playlist?list=PLMY3ZzVsXXyqN6yL9Snm6W19WhBPntj1Z
• QR Code Import Knowledge Base Article: https://support.mozilla.org/kb/thunderbird-android-import
• Release Channel Blog: https://blog.thunderbird.net/2025/03/thunderbird-release-channel-update/

The post VIDEO: Thunderbird 140.0 ESR “Eclipse” appeared first on The Thunderbird Blog.

Welcome back to another update on how things are going on mobile. 

Thunderbird for iOS

We’ve been going back and forth between database and JMAP for Thunderbird for iOS. Most of the visible work has flown into creating an initial JMAP library that we can use to access the parts that we need from Thunderbird for iOS. This work will continue into July as well. Progress so far means making JSON requests and parsing responses and making standard get/set/query requests. There is support for working with sessions as well.

In July we’ll have a few things to show for viewing actual folders and email messages. Very preliminary, but already quite some progress! I’m almost tempted to post the screenshots now but I’ll wait until next month. We’ll also be releasing a new (currently still internal) Testflight version when everything has landed.

Thunderbird for Android

We want to make Thunderbird for Android more accessible to contributors and improve some of our documentation. Part of that is our brand new testing guide which talks about which testing patterns to use, how to adhere to our naming conventions and some guidelines around fakes vs mocks. We’ve recently been talking about making more use of the Maestro testing framework, as it makes it very simple to add tests even for folks without engineering experience. 

Further we’ve made some strides on our overall architecture documentation. If you’ve been reluctant to contribute because of the learning curve, this might be your chance to make another attempt. Even if you are an existing contributor, we believe the docs will help you understand the codebase a bit better. Let us know what you think, if you see a way that our documentation can be improved go ahead and file an issue.

Next up, we’re nearing the end of the drawer updates we’ve been working on. We know a bunch of folks weren’t very happy with the navigation rail given the extra horizontal space it uses, and it being unclear which account you actually have selected. We’re returning the account selector to the top, and sporting a separate “Unified Account” where you can find not just your unified inbox, but also some other unified folders. If you’ve set up custom unified folders previously these will appear there as well. 

Additional updates

• Ashley has worked on sync debug tooling so we can get a better understanding of any issues related to emails not arriving in time.
• Jan has switched the EHLO string from 127.0.0.1 to ehlo.thunderbird.net to increase compatibility with email servers that don’t accept 127.0.0.1.
• João has improved accessibility of the contact pictures in the message view, and fixed an issue where the “Download Complete Message” button was hidden by the navigation bar.
• Rafael has been working on the foundations of in-app error notifications. He improved swiping actions for when the account does not have an archive folder set, to avoid surprises. Through this work a bunch of files have been migrated from Java to Kotlin, great work!
• Stefan has fixed an issue where some I/O errors were not correctly caught. I’m particularly excited about this since it smooths over the situation where you change from one network to the next, so that push email will arrive a little more reliably.
• Wolf has revamped some of our internal logging support to be more consistent. We really don’t need multiple different loggers and might want to change the implementation once in a while There has also been a bunch of Java/Kotlin conversion going on, and some refactoring in the local search code. Above mentioned work on the drawer and documentation was also Wolf’s work. 
• Shamim continues to rock the refactoring. By far the most Java to Kotlin conversion, fixing a crash when adding an account after removal, making threaded view update correctly when in the message list. Notably, the [Gmail] folder placeholder is now no longer visible, you’ll see the subfolders directly.

—
Philipp Kewisch (he/him)
Thunderbird Mobile Engineering | Mozilla Thunderbird
thunderbird.net

The post Mobile Progress Report – June 2025 appeared first on The Thunderbird Blog.

Hello once more from the Thunderbird development team! For many of our team members, the summer has started with our annual sprint to release ESR and enjoy a little time afk, as our colleagues in the southern hemisphere hunker down for winter and power through a pile of work down under.

Extended Support Release is alive!

For enterprise users (and those who have been using Thunderbird for a long time and found themselves on the Extended Support Release channel), the annual release “ESR 140 Eclipse” has made it to our update servers and will be pushed out over the next few weeks. 

We had initially planned to release within hours or days of the Firefox ESR release, but much of the ESR build process has changed in the last 12 months (largely due to the Firefox mozilla-central Git migration) – so we ended up learning a lot and took pause to release at a time that produced the best experience for the majority of our users. 

In the hours following the initial release, we have another build hot on its heels which includes some important patches and will ship today or tomorrow. Things move fast around here!

If waiting a year doesn’t sound appealing to you, our Monthly release may be better suited. It offers access to the latest features, improvements, and fixes as soon as they’re ready. Watch out for an in-app invitation to upgrade or install over ESR to retain your profile settings.

Exchange support in Daily

The EWS 0.2 milestone has been completed and the feature was turned on by default in Daily release to facilitate more manual QA testing. In order to provide test coverage on a variety of EWS server versions and configurations, we’re tackling in a few ways:

• Adding a small number of Hosted Exchange 2016 mailboxes to facilitate testing of all existing functionality at endpoints other than O365.
• Contacting enterprise partners who can help us test on their infrastructure – please get in touch if this might be you!
• Hosting our own EWS instance that allows us to configure a variety of security and authentication settings to ensure our code works for all
• Focusing on automated test coverage throughout the month of July

Since my last update, the team has grown even more and made great progress on items in our “Phase 2 operations” and “Phase 2 polish” milestones, with these features delivered recently:

• EWS-to-EWS move & copy for items and folders
• Authentication Error handling
• Server Version handling
• Threading support
• Folder updates & deletions during sync operations
• Folder cache cleanup
• Folder copy/move
• Bug fixes!

We plan to temporarily expand the team during July to include two more of our most experienced senior engineers to push this project over the finish line and tackle some remaining complexities:

• Automated test coverage
• Message filtering
• Setting as Junk/Not Junk
• Bug backlog

Keep track of feature delivery here.

Account Hub

The new email account feature was enabled as the default experience for users adding their second email account. It is now available in all release channels. We’re currently finalizing the UX and associated functionality that detects whether account autodiscovery requires a password, and reacts accordingly – which will hopefully be uplifted once stable.

We’re wrapping up the redesigned Account Hub UI for Address Book account additions this week, which we’ll enable for users on Daily and beta in the coming weeks. Look out for it in our Monthly release 142.

Global Message Database

Since the last update, we’ve landed a landslide of patches. Critical refactoring continues to clean and optimize the code, in many cases clearing the way for new beneficial protocol implementations.

To follow their progress, take a look at the meta bug dependency tree. The team also maintains documentation in Sourcedocs which are visible here.

Recent Features and Fixes

A number of other features and fixes have reached our Daily users this month. We want to give special thanks to the contributors who made the following possible…

• Even more improvements to notifications!
• Many, many port bugs to adapt Thunderbird to upstream changes
• Fix spell check and other windows impacted by Firefox code updates
• and many more listed in release notes for beta.

If you would like to see new features as they land, and help us squash some early bugs, you can try running daily and check the pushlog to see what has recently landed. This assistance is immensely helpful for catching problems early.

—

Toby Pilling

Senior Manager, Desktop Engineering

Thunderbird

The post Thunderbird Monthly Development Digest – June 2025 appeared first on The Thunderbird Blog.

The wait is over! Thunderbird 140 “Eclipse” has reached totality. From all of us at the Thunderbird project, from MZLA staff and the Thunderbird Council to our global community of contributors, we’re excited to announce the latest Extended Support Release has arrived.

Eclipse not only builds on Thunderbird 128 “Nebula,” but also the recent features and improvements from the Monthly Release channel. This latest release transforms your email experience with adaptive dark messaging and improved visual controls. Enhanced features keep everyday email tasks light and effortless, while the streamlined new Account Hub ensures adding new accounts is a snap.

Don’t like the order for your custom folders? Just click and drag to arrange them exactly how you want.

More Refinements & Updates

Experimental Exchange Support Natively set up a Microsoft Exchange account in Thunderbird by enabling a preference.

Export for Mobile Generate a QR code to quickly transfer your account settings and credentials to your Thunderbird for Android app.

Horizontal Scroll for Table View Lots of tabular data? Let the message list scroll horizontally, like a spreadsheet or file manager.

Bug Fixes and Improvements

Thousands of bug fixes and performance improvements to bring you the smooth, reliable Thunderbird experience you expect.

Looking Forward

Whether you’re waiting for the next Thunderbird ESR or total solar eclipse, we understand that sometimes you want new features, or that cosmic awe, sooner. While we can’t change the universe, you can now get the latest Thunderbird features as they land, instead of once a year. Switch to Thunderbird Release and enjoy monthly updates with the same dependable stability.

Thunderbird 140 Availability For Windows, Linux, and MacOS

Even with QA and beta testing, any major software release may have issues exposed after significant public testing. That’s why we are slowly enabling automatic updates until we’re confident no such issues exist. We do have a known issue where users sending mail through 32bit MAPI will be prompted for a password, unless they use the compose window.

We have enabled manual upgrade to 140 via Help > About, and you can upgrade now or wait to receive automatic updates. Thunderbird version 140.0 is also offered as direct download from thunderbird.net. Be sure to select ‘Thunderbird Extended Support Release’ in the ‘Release Channel’ drop-down menu.

For Linux users running Thunderbird from the snap or flatpak, 140 will be available within the next few weeks. Likewise, Thunderbird 140 will also arrive on the Windows store by mid-July.

The post Welcome to Thunderbird 140 “Eclipse” appeared first on The Thunderbird Blog.

Thunderbird for iOS

We’re growing a few more stars! We’re so happy to hear there is great interest in Thunderbird for iOS, and hope to reach a stage soon where you all can be more involved. Thank you, also, to those of you who’ve submitted an increasing number of ideas via Mozilla Connect.

Todd has been preparing the JMAP implementation for iOS, which will allow us to test the app with real data. We’re exploring the possibility of releasing the first community TestFlight a bit earlier by working directly with in-memory live data instead of syncing everything to a database upfront. The app may crash if your inbox has 30GB of email, but this approach should help us iterate more quickly. We still believe offline-first is the right path, and designing a database that supports this will follow soon after.

Further we’ve set up the initial localization infrastructure. This was surprisingly easy using Weblate’s translation propagation feature. We simply needed to add a new component to our Android localization project that pulls from the iOS repository. While Weblate doesn’t (yet?) auto-propagate when the component is set up, if there are changes across iOS and Android in the future, the strings will automatically apply to both products. 

Thunderbird for Android

We spent a lot of time thinking about the beta and making adjustments. Fast forward to June, we’re still experiencing a number of crashes. If you are running the beta, please report crashes and try to find out how to trigger them. If you are not using Beta, please give it a try and report back on the beta list or issue tracker. We’d greatly appreciate it! Here are a few updates worth noting for the month of May:

• Some folks on beta may have noticed the “recipient field contains incomplete input” error which kept you from sending emails. We’ve noticed as well, and halted the rollout of 11.0b1 on app stores where supported. Shamim fixed this issue for 11.0b2.
• Another important issue was when attaching multiple issues, only one image would be attached. This happens all the way back to 10.0, and we’ll release a 10.1 that includes this fix. Again thank you to Shamim!
• Final round of fixes from Shamim: new mail notifications can be disabled again, we have a bunch of new tests and refactoring, we have a few new UI types for the new preference system that Wolf created.
• Timur Erofeev solved a crash on Android 7 due to some library changes in dependency updates we didn’t anticipate
• Wolf is getting closer to finishing the drawer updates that we’re excited to share in a beta soon. He has also been working diligently to remove some of the crashes we’ve been experiencing on beta due to the new drawer and some of the legacy code it needs to fall back to. Finally, as we’re venturing into Thunderbird for iOS, Wolf has been thinking about the KMP (Kotlin Multiplatform) approach and added support to the Thunderbird for Android repository. He will soon separate a simple component and set things up so we can re-use it from Thunderbird for iOS.
• Rafael and Marcos have fixed some issues with the system bar appearing transparent. The issue has been very persistent, we’re still getting reports of cases where this isn’t yet resolved.
• Philipp has fixed an issue for our release automation to make sure the changelog doesn’t break on HTML entities.

I also wanted to highlight the new Git Commit Guide that Wolf created to give us a little more stability in our commits and set expectations for pull requests. We have a few more docs coming up in June, stay tuned. 

You could be on this list next month, please get in touch if you’d like to help out!

—
Philipp Kewisch (he/him)
Thunderbird Mobile Engineering | Mozilla Thunderbird

The post Thunderbird Mobile Progress Report: May 2025 appeared first on The Thunderbird Blog.

It’s been just over two months (!) since we first announced our upcoming Thunderbird Pro suite and Thundermail email service. We thought it would be a great idea to bring in Chris Aquino, a Software Engineer on our Services team, to chat about these upcoming products. We want our community to get to know the newest members of the Thunderbird family even before they hatch!

We’ll be back later this summer after our upcoming Extended Support Release, Thunderbird 140.0, is out! Members of our desktop team will be here to talk about the newest features. Of course, if you’d like to try the newest features a little sooner, we encourage you to try the monthly Release channel. Just be sure to check if your Add-ons are compatible first!

May Office Hours: Thunderbird Pro and Thundermail

Chris has been a part of the Thunderbird Pro products since we first started developing them. So not only is he a great colleague, he’s an ideal guest to help tell the story about this upcoming chapter in the Thunderbird story. Chris starts with an overview for each product that covers the features we have planned for each of our Thunderbird Pro products and Thundermail. We know how curious our community is about these products, and so our hosts have lots of questions for each product, and Chris is more than up to the challenge in answering them. We also make sure to point out how to get involved with trying, testing, and helping us improve these products by linking you to our repositories.

Watch, Read, and Get Involved

The entire interview with Chris is below, on YouTube and Peertube. There’s a lot of references in the interview, which we’ve handily provided below. We hope you’re enjoying these looks into what we’re doing at Thunderbird as much as we’re enjoying making them, and we’ll see you soon!

We also know some of you might only be interested in a single product, and so we’ve also made separate videos for each product!

COMPLETE VIDEO (Also on Peertube):

Slides:

Individual Videos:

Appointment

YouTube: https://youtu.be/7EOQL750wy8

TILVids: https://tilvids.com/w/sQBce3zn3gAQopCg9EMeBE

Thundermail

YouTube: https://youtu.be/WaycMTC94SA

TILVids: https://tilvids.com/w/hBR4gN5RvmzVv5ugsUx9Cy

Send

YouTube: https://youtu.be/DJWn84loerE

TILVids: https://tilvids.com/w/wm6xW6gzJ5BTRj7AoePaZW

Assist

YouTube: https://youtu.be/hcfERyCnfy8

TILVids: https://tilvids.com/w/27wUtpY4bWkNhLMbC8JnBs

Resources:

• ZDNet review of Appointment: https://www.zdnet.com/home-and-office/work-life/the-new-thunderbird-appointment-tool-is-thoroughly-impressive-and-free/
• TB Pro Announcement: https://blog.thunderbird.net/2025/04/thundermail-and-thunderbird-pro-services/
• TB Appointment Repo: https://github.com/thunderbird/appointment
• TB Send Repo: https://github.com/thunderbird/send-suite
• Beta Mailing List Sign Up: https://thundermail.com/ and https://tb.pro
• Stalwart: https://stalw.art
• Flower Intelligence: https://flower.ai/intelligence/
• Thunderbird Services Matrix Room: https://matrix.to/#/#tb-services:mozilla.org
• Thunderbird Merch Store (alas, no adult footie pajamas yet) North America: https://mozilla-na.myspreadshop.com/thunderbird?collection=irQGRGIyKo
• Thunderbird Merch Store Europe and Rest of World: https://mozilla-europe.myspreadshop.ie/thunderbird?collection=PMnUuLrvYM

The post VIDEO: Thunderbird Pro and Thundermail! appeared first on The Thunderbird Blog.

In this month’s Community Office Hours, we’re chatting with our director Ryan Sipes. This talk opens with a brief history of Thunderbird and ends on our plans for its future. In between, we explain more about MZLA and its structure, and how this compares to the Mozilla Foundation and Corporation. We’ll also cover the new Thunderbird Pro and Thundermail announcement And we talk about how Thunderbird put the fun in fundraising!

And if you’d like to know even more about Pro, next month we’ll be chatting with Services Software Engineer Chris Aquino about our upcoming products. Chris, who most recently has been working on Assist, is both incredibly knowledgeable and a great person to chat with. We think you’ll enjoythe upcoming Community Office Hours as much as we do.

April Office Hours: Thunderbird and MZLA

The beginning is always a very good place to start. We always love hearing Ryan recount Thunderbird’s history, and we hope you do as well. As one of the key figures in bringing Thunderbird back from the ashes, Ryan is ideal to discuss how Thunderbird landed at MZLA, its new home since 2020. We also appreciate his perspective on our relationship to (and how we differ from) the Mozilla Foundation and Corporation. And as Thunderbird’s community governance model is both one of its biggest strengths and a significant part of its comeback, Ryan has some valuable insights on our working relationship.

Thunderbird’s future, however, is just as exciting a story as how we got here. Ryan gives us a unique look into some of our recent moves, from the decision to develop mobile apps to the recent move into our own email service, Thundermail, and the Thunderbird Pro suite of productivity apps. From barely surviving, we’re glad to see all the ways in which Thunderbird and its community are thriving.

Watch, Read, and Get Involved

The entire interview with Ryan is below, on YouTube and Peertube. There’s a lot of references in the interview, which we’ve handily provided below. We hope you’re enjoying these looks into what we’re doing at Thunderbird as much as we’re enjoying making them, and we’ll see you next month!

VIDEO (Also on Peertube):

Resources

• The untold history of Thunderbird: https://blog.thunderbird.net/2023/11/the-untold-history-of-thunderbird/
• The Mozilla Foundation: https://wiki.mozilla.org/Foundation
• Thunderbird’s New Home at MZLA: https://blog.thunderbird.net/2020/01/thunderbirds-new-home/
• Community Office Hours with the Thunderbird Council: https://blog.thunderbird.net/2024/09/video-learn-about-the-thunderbird-council/
• The Mozilla Manifesto: https://www.mozilla.org/about/manifesto/
• Thundermail and Thunderbird Pro Announcement: https://blog.thunderbird.net/2025/04/thundermail-and-thunderbird-pro-services/
• Get Involved: https://www.thunderbird.net/participate/

The post VIDEO: Talking MZLA with Ryan Sipes appeared first on The Thunderbird Blog.

Here is an update of what Thunderbird’s mobile community has been up to in April 2025. With a new team member, we’re getting Thunderbird for iOS out in the open and continuing to work on release feedback from Thunderbird for Android.

The Team is Growing

Last month we introduced Todd and Ashley to the MZLA mobile team, and now we have another new face in the team! Rafael Tonholo joins us as a Senior Android Engineer to focus on Thunderbird for Android. He also has much experience with Kotlin Multiplatform, which will be beneficial for Thunderbird for iOS as well.

Thunderbird for iOS

We’ve published the initial repository of Thunderbird for iOS! The application doesn’t really do a lot right this moment, since we intend to work very incrementally and start in the open. You’ll see a familiar welcome screen, slightly nicer than Thunderbird for Android and have the opportunity to make a financial contribution.

Testflight Distribution

We’re planning to distribute Thunderbird for iOS through TestFlight. To support that, we’ve set up an Apple Developer account and completed the required verification steps.

Unlike Android, where we maintain separate release and beta versions, the iOS App Store will have a single “Thunderbird” app. Apple prefers not to list beta versions as separate apps, and their review process tends to be stricter. Once the main app is published, we’ll be able to use TestFlight to offer a beta channel.

Before the App Store listing goes live, we’ll use TestFlight to distribute our builds. Apple provides an internal TestFlight option that doesn’t require a review, but it only works if testers have access to the developer account. That makes it unsuitable for community testing.

Initial Features for the Public Testflight Alpha

To share a public TestFlight link, we need to pass an initial App Store review. Apple expects apps to meet a minimum bar for functionality, so we can’t publish something like a simple welcome screen. Our goal for the first public TestFlight build is to support manual account setup and display emails in the inbox. Here are the specifics:

• Initial account setup will be manual with hostname/username/password.
• There will be a simple message list that will only show the INBOX folder messages, with a sender, subject, and maybe 2–3 preview lines.
• You’ll have the opportunity to pull to refresh your inbox.

That is certainly not what you’d call a fully functional email client, but it could qualify for bare minimum functionality required for the Apple review. We have more details and a feature comparison in this document.

In other exciting news, we’re going to build Thunderbird for iOS with JMAP support first and foremost. While support on the email provider side is limited, we start with a modern email stack. This will allow us to build towards some of the features that email from the late 80’s was missing. We’ll be designing the code architecture in a way that adding IMAP support is very simple, so it will ideally follow soon after.

iOS Release Engineering and Localization

We’ve also gone through a few initial conversations on what the release workflow might look like. We’re currently deciding between:

• GitHub Actions with Upload Actions (Pro: very open, re-use of some work on the Thunderbird for Android side. Con: Custom work, not many well-supported upload actions)
• GitHub Actions with Fastlane (Pro: very open, well-supported, uses the same listing metadata structure we already have on Android. Con: Ruby as yet another language, no prior releng work)
• Xcode Cloud (Pro: built in to Xcode, easy to configure, we’ll probably get by with the free tier for quite some time. Con: Not very open, increasing build cost)
• Bitrise (Pro: Easy to configure, used by Firefox for iOS, we’ll get some support from Mozilla on this. Con: Can be pricy, not very open)

For now, our release process is pressing a button every once in a while. Xcode makes this very easy, which gives the release operations more time to plan a solution.

For localization, we’re aiming to use Weblate, just as Thunderbird for Android. The strings will mostly be the same, so we don’t need to ask our localizers to do double work.

Thunderbird for Android

We’re still focusing on release feedback by working on the drawer and looking to improve stability. April has very much been focused on onboarding the new team. I’ll keep the updates in this section a bit more brief, as we have less to explore and more to fix

• We’ve accepted a new ADR to change the shared modules package from app.k9mail and com.fsck to net.thunderbird. We’ll be doing this gradually when migrating over legacy code.
• Ashley has fixed a few keyboard accessibility issues to get started. She has also resolved a crash related to duplicate folder ids in the drawer. Her next projects are improving our sync debug tooling and other projects to resolve stability issues in retrieving emails.
• Clément Rivière added initial support for showing hierarchical folders. The work is behind a feature flag for now, as we need to do some additional refactoring and crash fixes before we can release it. You can however try it out on the beta channel.
• Fishkin removed a deprecated progress indicator, which provides slightly better support for Android watches.
• Rafael fixed an issue related to Outlook/Microsoft accounts. If you have received the “Authentication Unsuccessful” message in the past, please try again on our beta channel.
• Shamim continues on his path to refactor and move over some of our legacy code into the new modular structure. He also added support to attach files from the camera, and has resolved an issue in the drawer where the wrong folder was selected.
• Timur Erofeev added support for algorithmic darkening where supported. This makes dark mode work better for a wider range of emails, following the same method that is used on web pages.
• Wolf has been working diligently to improve our settings and drawer infrastructure. He took a number of much needed detours to refactor legacy code, which will make future work easier. Most notably,  we have a new settings system based on Jetpack Compose, where we will eventually migrate all the settings screens to.

That’s a wrap for April! Let us know if you have comments, or see opportunities to help out. See you soon!

The post Thunderbird for Mobile April 2025 Progress Report appeared first on The Thunderbird Blog.

Hello from the Thunderbird development team! With some of our time spent onboarding new team members and interviewing for open positions, April was a fun and productive month. Our team grew and we were amazed at how smooth the onboarding process has been, with many contributions already boosting the team’s output.

Gearing up for our annual Extended Support Release 

We have now officially entered the release cycle which will become our annual “ESR” at the end of June. The code we’re writing, the features we’re adding, the bugs we’re fixing at the moment should all make their way into the next major update, to be enjoyed by millions of users. This most stable release is used by enterprises, governments and institutions who have specific requirements around consistency, long-term support, and minimized change over time.

If waiting a whole year doesn’t sound appealing to you, our Monthly release may be better suited. It offers access to the latest features, improvements, and fixes as soon as they’re ready. Watch out for an in-app invitation to upgrade or install over ESR to retain your profile settings.

Calendar UI Rebuild

The implementation of the new event dialog hit some challenges in April with the dialog positioning and associated tests causing more than a few headaches when our CI started reporting test failures that were not easy to debug. Not surprising given the 60,000 tests which run for this one patch alone!!

The focus on loading data into the various containers continues, so that we can enable this feature and begin the QA process.

Keep track of feature delivery via the [meta] bug 

Exchange Web Services support in Rust

Our 0.2 release will make it into the hands of Daily and QA testers this month, with only a handful of smaller items left in our current milestone, before the “polish” milestone begins. The following items were completed in April:

• Connectivity check for EWS accounts
• Threading support
• Folder updates & deletions in sync
• Folder cache cleanup
• Folder copy/move
• Bug fixes!

Our hope is to include this feature set to users on beta and monthly release in 140 or 141.

Keep track of feature delivery here.

Account Hub

The new email account feature was “preffed on” as the default experience for the Daily build but recent changes to our Oauth process have required some rework to this user experience. We’re currently working on designing a UX and associated functionality that can detect whether account autodiscovery requires a password, and react accordingly.

The redesigned UI for Address Book account additions is also underway and planned for release to users on 25th May.

Global Message Database

We welcomed a new team member in April so technical onboarding has been a priority. In addition, a long list of patches landed, with the team focused on refactoring core code responsible for the management of common folders such as Drafts or Sent Mail, and significant changes to nsIMsgPluggableStore.

Time was spent to research and plan a path to tackle dangling folders in May.

To follow their progress, the team maintains documentation in Sourcedocs which are visible here.

New Features Landing Soon

A number of requested features and important fixes have reached our Daily users this month. We want to give special thanks to the contributors who made the following possible…

• Improvements to notifications
• Manual folder sorting improvements
• Several port bugs to correct bustage introduced by upstream changes
• and many more in the release notes for beta.

If you would like to see new features as they land, and help us squash some early bugs, you can try running daily and check the pushlog to see what has recently landed. This assistance is immensely helpful for catching problems early.

—

Toby Pilling

Senior Manager, Desktop Engineering

Thunderbird

The post Thunderbird Monthly Developer Digest – April 2025 appeared first on The Thunderbird Blog.

In this month’s Community Office Hours, we’re chatting with Vineet Deo, a Software Engineer on the Desktop team, who walks us through the new Account Hub on the Desktop app. If you want a sneak peak at this new streamlined experience, you can find it in the Daily channel now and the Beta channel towards the end of April.

Next month, we’ll be chatting with our director Ryan Sipes. We’ll be covering the new Thunderbird Pro and Thundermail announcement and the structure of MZLA compared to the Mozilla Foundation and Corporation. And we’ll talk about how Thunderbird put the fun in fundraising!

March Office Hours: The New Account Hub

Setting up a new email account in Thunderbird is already a solid experience, so why the update? Firstly, this is the first thing new users will see in the app. Thus, it’s important it has the same clean, cohesive look that is becoming the new Thunderbird design standard. It’s also helpful for users coming from other email clients to have a familiar, wizard-like experience. While the current account setup works well, it’s browser based. This makes it possible a user could exit out before finishing and get lost before they even started. This is the opposite of what we want for potential users!

Vineet and his team are also working to make the new Account Hub ready for Exchange. Likewise, they also have plans for a similar hub to set up new address books and calendars. We’re proud of the collaboration between back and frontend teams, and designers and engineers, to make the Account Hub.

Watch, Read, and Get Involved

But don’t take our word for it! Watch Vineet’s Account Hub talk and demo, along with a Q&A session. If you’re comfortable testing Daily, you can test this new feature now. (Go to File > New > Email Account to start the experience.) Otherwise, keep an eye on our Beta release channel at the end of April. And if you’re watching this after Account Hub is part of the regular release, now you know the feature’s story!

VIDEO (Also on Peertube):

Get Involved

• TB Beta Mailing List (to provide feedback on Account Hub once it lands): https://thunderbird.topicbox.com/groups/beta

The post VIDEO: The New Account Hub appeared first on The Thunderbird Blog.

Hello, everyone, and welcome to the Thunderbird for Android March 2025 Progress Report. We’re keeping our community updated on everything that’s been happening in the Android team, which is quickly becoming a more general mobile team with some recent hires. In addition to team news, we’re talking about our roadmap board on GitHub.

Team Changes

In March we said goodbye to cketti, the K-9 Mail maintainer who joined the team when Thunderbird first announced plans for an Android app. We’re very grateful for everything he’s created, and for his trust that K-9 Mail and Thunderbird for Android are in good hands. But we also said hello to Todd Heasley, our new iOS engineer, who started March 26. We also have just added Ashley Soucar, an Android/iOS engineer, who joined us on April 7. If all continues to go well, we’ll also be adding another Android engineer in the next couple of weeks.

Our Roadmap Board

Our roadmap board is now available! We’re grateful to the Council for their trust and support in approving it. As the board will reflect any changes in our planning, this is the most up-to-date source for our upcoming development. Each epic will show its objective and what’s in scope – and as importantly, what’s out of scope. The project information on the side will tell you if an epic is in the backlog or work in progress.

If you’d like to know what we’re working on right now, check out our sprint board.

Contribute by Triaging GitHub Issues

One way to contribute to Thunderbird for Android is by triaging open GitHub Issues. In March, we did a major triage with over 150 issues closed as duplicates, marked with ‘works for me,’ or elevating them up to the efforts and features described in the roadmap above. Especially since we’re a small team, triaging issues helps us know where to act on incoming issues. This is a great way to get started as a Thunderbird for Android contributor.

To start triaging bugs, have a look at the ‘unconfirmed’ issues. Try to reproduce the issue  to help verify that the issue exists. Then add a comment with your results and any other information you found that might help narrow down the issue. If you see users generally saying “it doesn’t work”, ask them for more details or to enable logs. This way we know when to remove the unconfirmed label. If you have questions along the way or need someone to confirm a thought you had, feel free to ask in the community support channel.

Account Drawer

Our main engineering focus in March has been the account drawer we shared screenshots on in the January/February update. Given the settings design includes a few non-standard components, we took the opportunity to write a modern settings framework based on Jetpack Compose and make use of it for the new drawer. There will be some opportunities to contribute here in the future, as we’d like to migrate our old settings UI to the new system.

We have a few crashes and rough edges to polish, but are very close to enabling the feature flag in beta. If you aren’t already using it and want to get early access, install our beta today.

I’d also like to call out a pull request by Clément, who contributed support for a folder hierarchy. The amazing thing here—our design folks were working out a proposal because we were interested in this as well, and without knowing, Clément came up with the same idea and came in with a pull request that really hit the spot. Great work!

Community Contributions

In addition to the folder hierarchy mentioned above, here are a few community activities in March:

• Shamim made sure the Unified Inbox shows up when you add your second account, retained scroll position in the drawer when rotating, removed font size customizations in favor of Android OS controls, flipped the default for being notified about new email and helped out with a few refactorings to make our codebase more modern.
• Sergio has improved back button navigation when editing drafts.
• Salkinnoma made our workflow runs more efficient and fixed an issue in the find folders view where a menu item was incorrectly shown.
• Smatek improved our edge to edge support by making the bottom Android navigation bar background transparent
• Husain fixed some inconsistencies when toggling “Show Unified Inbox”.
• Vayun has begun work to update the Thunderbird for Android app widgets to Jetpack compose (including dark theming)
• SttApollo has made the logo size more dynamic in the onboarding screen.

This is quite a list, great work! When you think about Thunderbird for Android or K-9 Mail, what was the last major annoyance you stumbled upon? If you are an Android developer, now is a good time to fix it. You’ll see your name up here next time as well

The post Thunderbird for Android March 2025 Progress Report appeared first on The Thunderbird Blog.

Hello again Thunderbird Community! It’s been almost a year since I joined the project and I’ve recently been enjoying the most rewarding and exciting work days in recent memory. The team who works on making Thunderbird better each day is so passionate about their work and truly dedicated to solving problems for users and supporting the broader developer community. If you are reading this and wondering how you might be able to get started and help out, please get in touch and we would love to get you off the ground!

Paddling Upstream

As many of you know, Thunderbird relies heavily on the Firefox platform and other lower-level code that we build upon. We benefit immensely from the constant flow of improvements, fixes, and modernizations, many of which happen behind the scenes without requiring our input. 

The flip side is that changes upstream can sometimes catch us off guard – and from time to time we find ourselves firefighting after changes have been made. This past month has been especially busy as we’ve scrambled to adapt to unexpected shifts, with our team hunting down places to adjust Content Security Policy (CSP) handling and finding ways to integrate a new experimental whitespace normalizer. Very much not part of our plan, but critical nonetheless.

Calendar UI Rebuild

The implementation of the new event dialog is moving along steadily with the following pieces of the puzzle recently landing:

• Title
• Border
• Location Row
• Join Meeting button
• Time & Recurrence

The focus has now turned to loading data into the various containers so that we can enable this feature later this month and ask our QA team and Daily users to help us catch early problems.

Keep track of feature delivery via the [meta] bug 

Exchange Web Services support in Rust

We’re aiming to get a 0.2 release into the hands of Daily and QA testers by the end of April so a number of remaining tasks are in the queue – but March saw a number of features completed and pushed to Daily

• Folder copy/move
• Sync folder – update
• Complete composition support (reply/forward)
• Bug fixes!

Keep track of feature delivery here.

Account Hub

This feature was “preffed on” as the default experience for the Daily build but recent changes to our Oauth process have required some rework to this user experience, so it won’t hit beta until the end of the month. It’s beautiful and well worth considering a switch to Daily if you are currently running beta.

Global Message Database

The New Zealand team completed a successful work week and have since pushed through a significant chunk of the research and refactoring necessary to integrate the new database with existing interfaces.

The patches are pouring in and are enabling data adapters, sorting, testing and message display for the Local Folders Account, with an aim to get all existing tests to pass with the new database enabled. The path to this goal is often meandering and challenging but with our most knowledgeable and experienced team members dedicated to the project, we’re seeing inspiring progress.

The team maintains their documentation in Sourcedocs which are visible here.

In-App Notifications

A few last-minute changes were made and uplifted to our ESR version early this month so if you use the ESR and are in the lucky 2% of users targeted, watch out for an introductory notification!
We’ve also wrapped up work on two significant enhancements which are now on Daily and will make their way to other releases over the course of the month:

• Granular control of notifications by type via EnterprisePolicy
• Enhanced triggering mechanism to prevent launch when Thunderbird is in the background

 Meta Bug & progress tracking.

New Features Landing Soon

A number of requested features and important fixes have reached our Daily users this month. We want to give special thanks to the contributors who made the following possible…

• Several colour scheme improvements and fixes.
• A long-standing feature request to add manual sort order for folders
• Fix to notification interaction with quick filter
• Multiple message selection correction
• and many more which are listed in release notes for beta.

As usual, if you want to see and use new features as they land, and help us squash some early bugs, you can try running daily and check the pushlog to see what has recently landed. This assistance is immensely helpful for catching problems early.

—

Toby Pilling

Senior Manager, Desktop Engineering

The post Thunderbird Monthly Development Digest – March 2025 appeared first on The Thunderbird Blog.

Today we’re pleased to announce what many in our open source contributor community already know. The Thunderbird team is working on an email service called “Thundermail” as well as file sharing, calendar scheduling and other helpful cloud-based services that as a bundle we have been calling “Thunderbird Pro.”

First, a point of clarification: Thunderbird, the email app, is and always will be free. We will never place features that can be delivered through the Thunderbird app behind a paywall. If something can be done directly on your device, it should be. However, there are things that can’t be done on your computer or phone that many people have come to expect from their email suites. This is what we are setting out to solve with our cloud-based services.

All of these new services are (or soon will be) open source software under true open source licenses. That’s how Thunderbird does things and we believe it is our super power. It is also a major reason we exist: to create open source communication and productivity software that respects our users. Because you can see how it works, you can know that it is doing the right thing.

The Why for offering these services is simple. Thunderbird loses users each day to rich ecosystems that are both products and services, such as Gmail and Office365. These ecosystems have both hard vendor lock-ins (through interoperability issues with 3rd-party clients) and soft lock-ins (through convenience and integration between their clients and services). It is our goal to eventually have a similar offering so that a 100% open source, freedom-respecting alternative ecosystem is available for those who want it. We don’t even care if you use our services with Thunderbird apps, go use them with any mail client. No lock-in, no restrictions – all open standards. That is freedom.

What Are The Services?

Thunderbird Appointment

Appointment is a scheduling tool that allows you to send a link to someone, allowing them to pick a time on your calendar to meet. The repository for Appointment has been public for a while and has seen pretty remarkable development so far. It is currently in a closed Beta and we are letting more users in each day.

Appointment has been developed to make meeting with others easier. We weren’t happy with the existing tools as they were either proprietary or too bloated, so we started building Appointment.

Thunderbird Send

Send is an end-to-end encrypted file sharing service that allows you to upload large files to the service and share links to download those files with others. Many Thunderbird users have expressed interest in the ability to share large files in a privacy-respecting way – and it was a problem we were eager to solve.

Thunderbird Send is the rebirth of Firefox Send – well, kind of. At this point, we have a bit of a Ship of Theseus situation – having rebuilt much of the project to allow for a more direct method of sharing files (from user-to-user without the need to share a link). We opened up the repo to the public earlier this week. So we encourage everyone interested to go and check it out.

Thunderbird Send is currently in Alpha testing, and will move to a closed Beta very soon.

Thunderbird Assist

Assist is an experiment, developed in partnership with Flower AI, a flexible open-source framework for scalable, privacy-preserving federated learning, that will enable users to take advantage of AI features. The hope is that processing can be done on devices that can support the models, and for devices that are not powerful enough to run the language models locally, we are making use of Flower Confidential Remote Compute in order to ensure private remote processing (very similar to Apple’s Private Cloud Compute). 

Given some users’ sensitivity to this, these types of features will always be optional and something that users will have to opt into. As a reminder, Thunderbird will never train AI with your data. The repo for Assist is not public yet, but it will be soon.

Thundermail

Thundermail is an email service (with calendars and contacts as well). We want to provide email accounts to those who love Thunderbird, and we believe that we are capable of providing a better service than the other providers out there. Email that aligns with our values of privacy, freedom and respect of our users. No ads, no selling or training AI on your data – just your email and it is your email.

With Thundermail, it is our goal to create a next generation email experience that is completely, 100% open source and built by all of us, our contributors and users. Unlike the other services, there will not be a single repository where this work is done. But we will try and share relevant places to contribute in future posts like this.

The email domain for Thundermail will be Thundermail.com or tb.pro. Additionally, you will be able to bring your own domain on day 1 of the service.

Heading to thundermail.com you will see a sign up page for the beta waitlist. Please join it!

Final Thoughts

Don’t services cost money to run?

You may be thinking: “this all sounds expensive, how will Thunderbird be able to pay for it?” And that’s a great question! Services such as Send are actually quite expensive (storage is costly). So here is the plan: at the beginning, there will be paid subscription plans at a few different tiers. Once we have a sufficiently strong base of paying users to sustainably support our services, we plan to introduce a limited free tier to the public. You see this with other providers: limitations are standard as free email and file sharing are prone to abuse.

It’s also important to highlight again that Thunderbird Pro will be a completely separate offering from the Thunderbird you already use. While Thunderbird and the additional new services may work together and complement each other for those who opt in, they will never replace, compromise, or interfere with the core features or free availability of Thunderbird. Nothing about your current Thunderbird experience will change unless you choose to opt in and sign up with Thunderbird Pro. None of these features will be automatically integrated into Thunderbird desktop or mobile or activated without your knowledge.

The Realization of a Dream

This has been a long time coming. It is my conviction that all of this should have been a part of the Thunderbird universe a decade ago. But it’s better late than never. Just like our Android client has expanded what Thunderbird is (as will our iOS client), so too will these services.

Thunderbird is unique in the world. Our focus on open source, open standards, privacy and respect for our users is something that should be expressed in multiple forms. The absence of Thunderbird web services means that our users must make compromises that are often uncomfortable ones. This is how we correct that.

I hope that all of you will check out this work and share your thoughts and test these things out. What’s exciting is that you can run Send or Appointment today, on your own server. Everything that we do will be out in the open and you can come and help us build it! Together we can create amazing experiences that enhance how we manage our email, calendars, contacts and beyond.

Thank you for being on this journey with us.

—

Ryan Sipes
Managing Director of Product
Thunderbird

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