Thunderbird Blog

> Mozilla started transitioning Thunderbird out of their umbrella while TB is still highly dependent on Firefox code.

If you are referring to Mozilla Messaging and the period to 2012, no the only transitioning was in terms of product functionality. The community organized in 2014, unaffiliated with Mozilla, and it's not until about 2018 when staff were hired that community leadership were able to seriously reduce technical debt. But seriously reducing dependency on Firefox code is some distance away.

> Maybe we need a successor to Thunderbird? Something that's not tied to Firefox so much?

You are looking a millions of dollars paid developer time.

> Because it seems like we can't trust Mozilla and however many unpaid/underpaid volunteers to maintain it well enough.

Mozilla are not running the show here, the community is.

Perhaps it's difficult to keep up with the history, but https://blog.thunderbird.net/ has past relevant postings, plus developer and other mailing lists. To cite a couple, big changes in encryption https://blog.thunderbird.net/2019/10/thunderbird-enigmail-and-openpgp/ https://mail.mozilla.org/pipermail/tb-planning/2019-December/007286.html and development priorities http://lists.thunderbird.net/pipermail/maildev_lists.thunderbird.net/2019-November/002024.html which includes a new address book.

There is a significant professional development staff which is nicely paid, and the number of developers will soon double.…

I did back in February, but I'm unlikely to be able to completely accurately recount that now.

One thing I do remember is Ryan explaining how just being willing to directly ask people for money has been surprisingly effective.

It's also worth putting Thunderbird's relationship to Mozilla in proper perspective: for all intents and purposes, Thunderbird is a completely independent project. Since 2017 (https://blog.thunderbird.net/2017/05/thunderbirds-future-home/), the Mozilla Foundation has primarily acted as Thunderbird's fiscal home, providing support for donations / bookkeeping / taxes / legal matters much in the same way that the Software Freedom Conservancy hosts Git, Homebrew, Inkscape and others, or how Software in the Public Interest hosts PostgreSQL, systemd, Xorg, FFmpeg, 0 A.D, and more.

If I understand last year's MZLA Technologies announcement correctly (https://blog.thunderbird.net/2020/01/thunderbirds-new-home/), it sounds similar to the split between the Mozilla Foundation and the Mozilla Corporation, where the former is a legal non-profit and the latter entity is for-profit and able to enter into commercial, revenue-generating agreements, but still wholly owned by the non-profit Foundation.

...But you should really listen to the podcast, I could be getting all of this wildly wrong.

We implemented this in the Daily build of the desktop app last year, using a staging environment for Firefox Sync. But Firefox Sync is called Firefox Sync because it’s built for Firefox. Thunderbird profiles, in comparison, have a lot more data points. This meant we had to build something completely different. As we started to spin up Thunderbird Pro, we decided it made more sense to have a Thunderbird account that would manage everything, including Sync. Unfortunately, this meant a lot of delays. So Sync is still on our radar, and we hope to have it next year, barring further complications. Source: https://blog.thunderbird.net/2025/09/state-of-the-thunder-mozilla-connect-updates/

In other words, it was more work to adapt Firefox Sync than they thought at the beginning. It's still actively developed so finger crossed it's coming soon.

So much negativity in this thread, jeez.

I love current Thunderbird but it undeniably has its issues. Firstly, of course this is subjective, but its UI is starting to look dated. Lots of you are complaining about modern UIs, but I think the designs [0][1] look great and are much more readable than the current design, which looks straight out of Ubuntu 8.04.

Then there are some major UX issues, the most obvious one being the lack of conversation view, which is how pretty much everybody expects an email client to work in 2023. Supernova implementing that is reason enough to be excited about the release.

I can't wait to try it out - keep up the awesome work, team!

[0] https://developer.thunderbird.net/planning/roadmap

[1] https://blog.thunderbird.net/2022/11/thunderbird-supernova-preview-the-new-calendar-design/

Thunderbird operates independently within Mozilla:

> There was a time when Thunderbird’s future was uncertain, and it was unclear what was going to happen to the project after it was decided Mozilla Corporation would no longer support it. But in recent years donations from Thunderbird users have allowed the project to grow and flourish organically within the Mozilla Foundation. Now, to ensure future operational success, following months of planning, we are forging a new path forward. Moving to MZLA Technologies Corporation will not only allow the Thunderbird project more flexibility and agility, but will also allow us to explore offering our users products and services that were not possible under the Mozilla Foundation

https://blog.thunderbird.net/2020/01/thunderbirds-new-home/

Thunderbird lives in an entity called MZLA, created by Mozilla and the Thunderbird Council (the elected open source community leadership) to be the legal and financial home to Thunderbird.

MZLA, which I lead, receives only money via donations from donors. We are a for-profit because the IRS is very skeptical of nonprofits who develop FOSS software (someone down below linked to a bunch of great links on this topic). We, do, however publish tons of information on what we are doing on our blog, and we are open source and a community run project, so if you really want to go deep on this - come join us in making Thunderbird.

Great links:

https://blog.thunderbird.net

https://www.thunderbird.net/en-US/participate/