Over the past several weeks, we have been welcoming early users from our waitlist into Thundermail, a few waves at a time. Many of you are now setting up your accounts, trying things out, and sharing your thoughts with us.

Naming updates

You may have noticed that we are now saying Thundermail more often, and Thunderbird Pro less.

Thunderbird Pro started as the name for our subscription services, including Thundermail, Appointment, and Send. But early feedback made two things clear: people cared most about Thundermail, and “Pro” created confusion about whether Thunderbird itself was becoming a paid or limited product.

So, to clarify things, Thunderbird Pro is now simply Thundermail: the email service from Thunderbird, with features like Appointment and Send included.

The Thunderbird Desktop and Mobile apps remain exactly what they are today: powerful, compatible with any email service, and free.

What we learned so far

Every day, members of our team are reading through your survey responses, your messages in the Thundermail Early Bird community chat, your support requests, and every new idea and vote on the board. We discuss what we are hearing, and we sort it into what we can address right away and what we want to plan for. Then we keep working in the open, where you can see what we are up to and tell us when something is not quite right.

Here are some of the things we’ve learned so far:

• Custom domains matter a lot. Many called this out directly, along with support for unlimited custom domain aliases. Several responses said these features stood out compared to other email providers.
• Multi-factor Authentication saw a lot of requests on the ideas board, and we listened. This is now in progress and will be available soon.
• Users appreciate that Thundermail is open and works with any email app. It has always been our intention to stick to open standards so Thundermail stays easy and open to use with Thunderbird or any other app. 
• A bit of surprise that calendar and contacts are included. Apparently we should probably talk about that more.
• DNSSEC and DANE support picked up a lot of votes and is now on the roadmap.
• Requests for more pricing tiers and plans were frequently mentioned, which we will be adding once Thundermail is out of beta and open to the general public.
  • https://ideas.tb.pro/p/additional-pricing-tiers
  • https://ideas.tb.pro/p/a-la-carte-pricing

However, there was one request which came through louder than any other…

Webmail

Webmail was, by a wide margin, the most requested idea from our community, and whereas we had it in the plans for down the road, many people expected this to be a feature available from day one.

We moved webmail to the top of the list, shifted resources into the work behind it and we are excited to share that an early alpha version of it is coming next month. As with most early releases, it will have some rough edges, but will also allow for a much more interactive user experience for our beta testers. Everyone will have a vote in how it’s shaped for the future.

A look at what is coming next

• Webmail! Arriving soon.
• Two factor authentication is now in progress.
• More reliable email, as we keep fine tuning things behind the scenes, training global mail servers and spam filters.
• Onboarding improvements for a smoother first time sign-up flow.

Send and Appointment

Our scheduling and secure file sharing tools are still here, and they are still part of your subscription. Our main focus right now is Thundermail and webmail, but we are continuing to care for both with steady improvements along the way.

• Send: Improved Thundermail integration, providing end-to-end encrypted file attachments without the need for a separate add-on. Users on our Daily version can already test this feature today.
• Appointment: Streamlined the sign up flow, added an easy one click connection with the Thundermail calendar, and refreshed the calendar view design.

We’re looking for more ideas

If you are an Early Bird, we would love for you to visit our ideas board to share your suggestions and vote on the ones you would most like to see. We really do read every single one.

And if you have not been invited yet, you can join the waitlist. More waves are going out soon, and we are looking forward to welcoming you onboard.

Thank you for helping us build Thundermail.

The post Thundermail June 2026 update: what we learned after the first few waves of invites appeared first on The Thunderbird Blog.

One of the most exciting aspects of bringing Thunderbird Pro to life is the opportunity to build an email service from Thunderbird together with our community, giving users the control and freedom they expect without relying on third party email service providers.

Over the past few months, we’ve been checking in with our community through quick surveys, and the feedback is clear: people care most about Thundermail. We’re listening and working to deliver what you expect as quickly as possible, focusing our resources on building a great Thundermail experience first, with Appointment and Send as power features alongside that foundation. We’re also adjusting the initial price to better align with your expectations.

We’ll be sending out the first wave of Early Bird Beta invites next month. If you haven’t already, please join the waitlist HERE and keep an eye on your inbox. We’re excited to get Thundermail into your hands and continue building it together.

Latest Thundermail Developments

Our work right now is focused on making Thundermail reliable, easy to set up, and ensuring a smooth onboarding experience with an intuitive design, both visually and functionally.

Sign-in and Setup

A new connection flow is in development that will make it much easier to add a Thundermail account to Thunderbird, including options like QR code setup and deeper integration within the app. We have also fixed a range of sign in issues, improved domain setup, and made it easier to move from account creation to actually using the service.

The account dashboard has been updated for a cleaner look, smoother onboarding, and easier access to the key details our users care about.  Configuring settings like app passwords, custom domains and aliases are now front and center when you first sign in.

Infrastructure

On the infrastructure side, we’re continuing to improve stability and performance. This includes completed work on upgrading Stalwart to strengthen spam detection so legitimate emails are far less likely to end up in spam, along with improvements to how we monitor the services so problems are easier to catch and less likely to affect users. Everyday actions like archiving and managing settings should feel more intuitive for users, and the web app, add-ons, and related services now work together more smoothly.

April Onward

• Next up for the account experience is better alias and custom-domain handling, and even better integration between Thunderbird and the web account flow.
• The dashboard is also getting another round of refinement so settings, account details, and subscription information are easier to understand at a glance.
• Thundermail work continues by focusing on reliability and security, including aliases, delivery, transport security, and admin access controls.
• There will also be a final layer of polish across the entire experience between the web app, add-on, and desktop flows.
• Finally: Webmail is moving up our priority list. While still early, development is actively progressing and we’re aiming to bring a usable experience much sooner than originally planned.

Progress on Appointment and Send

While Thundermail is our primary focus, work on other Thunderbird Pro services is continuing.

For Appointment, we’ve made progress on reliability and backend performance, including improvements to how calendar tasks are processed and fixes to event handling. Our priorities heading up to the release are also focused on reliability, with refinement on calendar connections, event syncing, Zoom access, and a simpler first-time setup flow.

For Send, we’ve made substantial visual improvement so that it feels like a more natural part of Thunderbird Pro. We’ve also made a number of security improvements and are continuing to evaluate infrastructure choices to ensure long term reliability. Our priorities for Send in the coming months include better encryption-key handling and clearer password-protected downloads.

What’s Next

We’ll begin inviting people from the waitlist into the Early Bird beta shortly. If you haven’t signed up yet, now’s the time. Your feedback will directly shape how Thundermail evolves.

For more up to date news, check out our services roadmap at: https://roadmaps.thunderbird.net/services/

If you want to get involved in the direction of these features or want to contribute ideas to the team, you can visit https://ideas.tb.pro/.

The post Thunderbird Pro April 2026 Update appeared first on The Thunderbird Blog.

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

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

A Stronger Core, Built to Last

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

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

Faster Updates, Delivered Monthly

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

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

Thunderbird Meets Exchange

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

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

Mobile Moves Forward

Thunderbird’s mobile story continued to grow in 2025.

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

Introducing Thunderbird Pro

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

Thunderbird Pro will include:

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

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

Looking Ahead to 2026

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

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

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

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

All of our work is funded solely by individual donations from our users and community.
Help support the future of Thunderbird!
For other ways to get involved with the Thunderbird project, visit our participate page.

The post Thunderbird 2025 Review: Building Stronger for the Future appeared first on The Thunderbird Blog.

As we get ready for the Thunderbird Pro launch, we want every service we offer to be secure and worthy of the trust our community places in us. That means being honest about where we stand today and the work we are doing to meet the promises we are making.

Recently we partnered with OSTIF, the Open Source Technology Improvement Fund, and 7ASecurity to perform a full security audit of Thunderbird Send. As previously introduced, Send is an end-to-end encrypted large file sharing service that will be part of the overall Thunderbird Pro subscription suite coming in 2026. It is built on the foundation of the original Firefox Send project, although much has changed since those days.

While the audit focused on Send, the 7ASecurity team also reviewed parts of our shared infrastructure. That extra visibility resulted in meaningful hardening improvements across all of our products.

This was a whitebox audit, which means the auditors had full access to our systems and source code. They reviewed both the client and server sides of the service. They also carried out supply chain analysis, where they examined how our dependencies are managed, and threat modelling, which helps identify how attackers might approach a system even if there is no known exploit today.

The Thunderbird team has already addressed most of the items in the report, including all critical vulnerabilities. This also includes almost all non-critical hardening recommendations.  A few require more time because they relate to the organization of our broader infrastructure. For example, all Thunderbird Pro services currently run under a single AWS account. This is fairly normal in the early stages of building a platform. As the services mature and become more distinct, we will split them into separate accounts for stronger isolation.

The audit highlighted two vulnerabilities. One was critical and one was high. There were also twenty recommendations for further strengthening and improvement. One of the issues involved an API endpoint that had the potential to expose some user data without requiring authentication and another issue created the possibility of a denial of service attack. While neither issue actually happened,  the conditions that made it possible needed to be removed. Both of these were addressed and fixed in April.

The auditors also noted theoretical paths that could lead to privilege escalation, where attackers use one part of a system to gain more access than intended. This does not mean a privilege escalation exists today, but that some patterns could be tightened to prevent them in the future. These concerns apply only to older infrastructure, such as where we were running Appointment Beta. Once we migrate these users from appointment.day to the new appointment.tb.pro, we will retire the older systems entirely.

Another recommendation involves adding build attestations. These allow anyone to verify that a software build came from us and has not been tampered with. This is something we plan to implement in 2026.

Not everything in the report was a list of problems. In fact, the auditors highlighted several positive aspects of the collaboration. Their notes describe a team that was prepared and organized from the beginning, which allowed the audit work to begin without delays. Communication was smooth through email and a shared Element channel. The Send engineering team was consistently helpful and responsive, providing access and information whenever needed. The auditors also appreciated that we gave them full staging visibility, documentation, test accounts and source code. Their updates throughout the process were structured and consistent. The final report even comments on the clarity of the project as a whole, which helped them form a well informed view of our security posture.

The report closes with detailed guidance and commentary, but it also reflects confidence that Thunderbird is taking the right approach to security. That is exactly why we welcome third party audits. Open source only works when everyone can see the work, question it and verify it. Thunderbird Pro will follow those same values as it develops into a complete ecosystem of secure, privacy respecting services.

We will continue improving Send and the rest of our Pro services, and we look forward to sharing more as we get closer to launch. Thank you for being part of this journey and for pushing us to build something stronger.

The full report can be found here.

The post Thunderbird Send Security Audit with OSTIF and 7ASecurity appeared first on The Thunderbird Blog.