As 2025 winds down, its time to start thinking of what we want to achieve for our Android AND iOS apps next year. Alessandro walks us through the 2026 mobile roadmap, covering our urgent priorities, feature wish list, and a glimpse at our upcoming design plans for the entire Thunderbird project.

Resources:
 Current Android Roadmap: https://github.com/orgs/thunderbird/projects/19
TB Pro Announcement: https://blog.thunderbird.net/2025/04/thundermail-and-thunderbird-pro-services/
Mobile Development Matrix: https://matrix.to/#/#tb-mobile-dev:mozilla.org
Thunderbird for Android GitHub Issues: https://github.com/thunderbird/thunderbird-android/issues

If you can believe it, Thunderbird for Android has been out for just over a year! In this episode of our Community Office Hours, Heather and Monica check back in with the mobile team after our chat with them back in January. Sr. Software Engineer Wolf Montwé and our new Manager of Mobile Apps, Jon Bott look back at what the growing mobile team has been able to accomplish this last year, what we’re still working on, and what’s up ahead. 

Welcome back to another State of the Thunder! In this episode, Managing Director Ryan Sipes is leading us through how the Thunderbird roadmap. Unlike other companies where roadmaps are driven solely by business needs, Thunderbird is working with our community governance and feedback from the wider user community to keep us honest even as we move forward.

Resources:
Mozilla Manifesto: https://www.mozilla.org/en-US/about/manifesto/
Share big ideas: https://connect.mozilla.org
Report desktop bugs: https://bugzilla.mozilla.org
Report Android bugs: https://github.com/thunderbird/thunderbird-android/issues/
Engage with the Thunderbird Council: https://council.thunderbird.net
Desktop roadmap: https://developer.thunderbird.net/planning/roadmap
Mobile roadmap: https://developer.thunderbird.net/planning/roadmap 

We're back with our twelfth episode of the State of the Thunder! In this episode, we're talking about community initiatives, filling you in on Android development, and finishing our updates on popular Mozilla Connect requests, including true Conversation View!

State of the Thunder is back after a short hiatus for a new season of answering questions and providing our community with updates on all our products, from mobile and desktop clients to the upcoming Thunderbird Pro! In our first episode of the new season, Alessandro and new cohost Michael Ellis tackle a new batch of your questions with help from members of the Thunderbird team and community. Then they provide updates on the 20-ish top Thunderbird suggestions in Mozilla Connect. 

Welcome back to State of the Thunder! In this edition, we're taking more community questions on a range of topics. From improving Settings to the role of Add-ons and more, the Thunderbird team is tackling your most urgent inquiries!

In the latest State of the Thunder, we're answering your questions about the upcoming Thunderbird Pro offerings and introducing our new head of Community Programs.

Michael Ellis is here to help us better serve our community, and he's placed a call for ideas on Mozilla Connect for ideas to improve the Thunderbird community: https://connect.mozilla.org/t5/discussions/have-ideas-to-improve-the-thunderbird-community/m-p/100264#M38972

Question 1: With these new services, will there be less effort spent on desktop and mobile?
Answer: No! Lately we've added several new developers to our desktop and mobile teams. TB Pro is a collecting of projects (not products) that mean to coexist besides our core products and fill in missing pieces for users.

Question 2: Why is Appointment being developed as a stand-alone?
Answer: As a stand-alone, users can adapt it for their individual use, and core users don't have to use it if they don't want to. Also, this gives us time to help the underlying protocols add support for what Appointment needs to run natively.

Question 3: Can you deploy Appointment on your own infrastructure?
Answer: Yes! We know many of our users like to self-host and so we wanted this option. But offering to manage it on our own infrastructure is not only good for people who don't want to manage it themselves, but it's an opportunity to not only keep Thunderbird financially sustainable but to raise the resources to make it truly competitive.

Question 4: Are there plans to make Send part of the core Thunderbird app?
Answer: No, not for the foreseeable future. We'd like to have it as an opt-in system add-on. We still have Filelink, which has allowed us to build Send. Developing Send can possibly allow us to expand on Filelink's abilities!

Question 5: In Send, is there a file size limit for each file?
Answer: As far as we know, no. You'll have a limit of how much storage you'll have, which right now we're imagining will be 500GB for a normal subscription. Subscription costs will both pay for the storage itself and its management. As Send is open source, we'll have free options for folks who want to self host with their own storage.

Question 6: Will I be able to use Thundermail with another client?
Answer: Of course! As you can imagine, we're big fans of open standards! Thundermail will also support JMAP.

Question 7: Any plans for future Google-like products connected to Thundermail?
Answer: This is largely up to the community! We have no shortage of ideas how we could expand TB Pro into those spaces, but this depends on our success. (So be sure to sign up for the mailing list and use the service if you us to move closer to a fully featured suite.) For some of those services, stakes are very high, so before moving into them we'd want to be certain we could do them well.

Question 8: Do we have a public roadmap for these projects?
Answer: We've started a process to make a public roadmap, along the lines of our mobile roadmap which shows current and planned sprints. This will be done in collaboration with the Thunderbird Council and will help our community get involved with these projects.

Resources:
Call for ideas to improve the community: https://connect.mozilla.org/t5/discussions/have-ideas-to-improve-the-thunderbird-community/m-p/100264#M38972
Consensus scheduling proposed standard: https://datatracker.ietf.org/doc/draft-ietf-calext-vpoll/
Filelink info: https://support.mozilla.org/kb/filelink-large-attachments
TopicBox Mailing Lists: https://thunderbird.topicbox.com/latest
Thunderbird GitHub Repositories: https://github.com/thunderbird
Bugzilla: https://bugzilla.mozilla.org/
Thunderbird Development Docs: https://developer.thunderbird.net/

Welcome back to the latest State of the Thunder! In this recording, we're eating frogs (metaphorically) and checking in on our roadmap progress, sharing our tips and tricks for Thunderbird development tools, and talking about the hows and whys of our fundraising campaigns.

In this latest State of the Thunder, we're discussing the upcoming yearly ESR, 140.0, which is due out June 24, 2025. We explain our numbering convention and our different channels, which comes from Firefox, and the difference between ESR, Release, Beta, and Daily. Find out why we're encouraging to use the monthly Release channel, but how this won't take anything away from ESR. Learn more about what channel is right for you (especially if you use add-ons), how to help us with using Beta and Daily, and how to safely move between ESR and Release. And as always, we finish with a community shoutout!

Resources: 

• What Train is It Now: http://whattrainisitnow.com
• Monthly Release Channel Blog Post: https://blog.thunderbird.net/2025/03/thunderbird-release-channel-update/
• Choosing a Release Channel: https://support.mozilla.org/kb/choosing-thunderbird-release-channel
• Testing Beta Support Article: https://support.mozilla.org/kb/thunderbird-beta
• Testing Daily Support Article: https://support.mozilla.org/kb/thunderbird-daily
• Release Channel Support Article (with info on safely downgrading): https://support.mozilla.org/kb/thunderbird-release
• Add-on Compatibility Add-on: https://addons.thunderbird.net/thunderbird/addon/addon-compatibility-check/
• tilorenz's Calendar grid patch: https://phabricator.services.mozilla.com/D251992

We're back with another State of the Thunder! In Volume 6, we're discussing the complexities bringing the monthly Release channel to snap and flatpak, increasing accessibility for assistive technologies, our relationship with Mozilla, why building Thunderbird is hard (and how we're trying to make it less so), and more! 

In the fifth volume of State of the Thunder, we're focusing on priorities. How do we begin on a priority roadmap project? How do we decide what to release and when to release it? And how do we adjust priorities for the benefit of our users? Additionally, we have news about Thunderbird Sync (!), what MZLA is doing to improve the open ecosystem, and updates on Thunderbird Pro and the mobile apps.