Betterbird Blog

Placing advertisements on the Thunderbird start page was under discussion years ago when our CEO was still serving on the Thunderbird Council. Back then, request received by certain advertisers were deemed incompatible with the Thunderbird mission.

Of course, the in-product start page is seen by many users, and therefore offers itself to draw attention to hand-picked relevant products or partners. A few days ago, we were contacted by the CEO of Forward Email. This company offers full mail hosting for people who have registered their own domain, or just mail forwarding. As a "test balloon", we agreed to show a recommendation for their products on our start page, to see where the collaboration can lead.

We're going to try out their SMTP service, since the outgoing mail server that comes with our hosting package at the German hosting provider Hetzner sometimes doesn't have the best "reputation", and we end up sending mail via Gmail.

Update: Following Forward Email's instructions, we configured SPF, DKIM and DMARC, and hey, now we have an alternative outgoing server. Definitely a win for our project! Their setup doesn't force you to transfer the MX records to them, so it gives you the flexibility you may need. Disclaimer: We're using a paid plan, so all this is not part of the free plan.

Any users who don't want to see the advertisement can add an ads=no parameter to the Betterbird start page location, so is becomes:

https://www.betterbird.eu/start?ads=no&locale=%LOCALE%&version=%VERSION%&channel=%CHANNEL%&os=%OS%&buildid=%APPBUILDID%

There is also a dark version of the start page:

https://www.betterbird.eu/start/indexd.php?locale=%LOCALE%&version=%VERSION%&channel=%CHANNEL%&os=%OS%&buildid=%APPBUILDID%

which can be modified to:

https://www.betterbird.eu/start/indexd.php?ads=no&locale=%LOCALE%&version=%VERSION%&channel=%CHANNEL%&os=%OS%&buildid=%APPBUILDID%

Here a message from the Betterbird CEO:

Dear followers of the Betterbird blog,

You may have asked yourself why we're self-hosting our own blog instead of publishing on social media to potentially reach a wider audience. The reason is simple: One of my principles is to only publish on media which I control, or at lease have moderator status, like on Reddit. I considered creating an account on Instagram, but was concerned about being affected by some random unjustified decision of the platform operator. Sadly, today this fear became reality as my personal Instagram account was blocked, stating that (quote): [the] account, or activity on it, doesn't follow our Community Standards.

That's totally surprising since the last post was made in more than two years ago, in January 2023, and the last trivial direct message sent was 50 days ago. So which activity were they referring to? 1.5 hours later the account was unblocked again after I had submitted a whole lot of personal data, including a selfie. Horrible.

Thanks for following us!

Import of data from the local PST files of a Microsoft Outlook profile was not working well in Thunderbird before 2011, when famous Russian developer Mike Kaganski^*) re-implemented it in bug 207156. His work was committed here with this changeset. That was in 2011 in Thunderbird 6. Back then, our project leader was working with Mike, mostly doing testing. Mike did a few more tweaks, for example here and here, so the feature was stable that year in Thunderbird 11.

With the advent of JS Mime, a new implementation of MIME processing written in JavaScript, Outlook import broke again in Thunderbird 38 due to threading issues. The fix was made in this bug ready for Thunderbird 60 by our project leader.

(The text below has been corrected on 8th November 2025, the initial information was incorrect.)

It's been working since then, but the advent of Outlook 2013/2016/2019, Office 365 and the modern Outlook app have changed the situation. Here is what is still working to this very day:

To import a PST with Outlook 2013/2016/2019 or Outlook 365 installed, add it to an IMAP profile (with OST file) as an additional data file.

This screenshot was taken after a successful import from Outlook 2010: It is possible that modern versions of Betterbird/Thunderbird have additional bugs, so if there is an issue, we recommend using an older version, for example Thunderbird 12 (we didn't test it). Older versions also give a more informative summary panel that the new kids on the block who took over Thunderbird axed in version 128 (bug 1851608):

If you're using Outlook 2013/2016/2019 or Outlook 365 on a POP account or the modern app, you will see this:

*) Mike is famous for cracking bug 393302, the dreaded MAPI x64 bug, that no one had been able to solve and that prevented Thunderbird from shipping 64-bit binaries. That was back in 2019, and the fix was backported to Thunderbird 60.

We had a few reports from the United States and Australia regarding slow download speeds for our larger binary files (.exe, .zip, .tar.xz and .dmg). Currently all files are hosted at our hosting provider in Germany, so "overseas" users are suffering from transatlantic (or transpacific) latency and limited peering bandwidth.

Therefore we made downloads also available via the Bunny Content Distribution Network. In Firefox, it looks like this:

This is a paid service, so the project has to finance every download. If our total download volume of currently 3.5 TB per month ran via this service, we would incur a considerable cost.

Therefore using CDN is a click away from the regular download page at www.betterbird.eu/downloads/, and we ask our users to use the service with care. We assume that no European user would need it. If the costs run too high, we will have to restrict this to certain regions.

Some Mondays are quiet, others are busy. Yesterday we had a very busy day fixing these bugs:

1. Edit headers not working for local folders with maildir storage.
2. Developer Toolbox not working in localised builds due to a repack error.
3. Custom icon not working on about box and some other panels.
4. Disappearing new lines in plain text edit. We picked up the report from a newsgroup. This was a bug in the upstream Mozilla editor.
5. Account colours not respecting the preference for "full row colour" due an error in rebasing our patch to the 140 codebase.

We provided "latest build" versions of the current version 140.3.0, so affected users can use a fixed version straight away.

In the context of testing Edit headers, we discovered and upstream Thunderbird bug which led to the second edit on the same IMAP message not being reflected correctly in the message list and header pane. A regression in the Thunderbird 140 codebase, it was working in 115 and 128. The add-on Header Tools Improved is also affected. That bug we didn't manage to fix yet. (Update 28 Sept. 2025: Fixed!)

Yesterday we shipped a blue Betterbird cap to the Netherlands; the one in the photo will go to an aficionado in Germany.

We procure the caps at Top Hats Calella; the last one we bought was still €13, but now the manufacturer has switched to sustainable cotton, and the price will go up to €14 for the next order. The shop manager in Calella has the pattern for our trademark on file and he takes great care that every cap will turn out perfect.

From the shop, we take the caps to our headquarter. Either we ship them with Spanish Correos, or we ship them to supporters in Germany with Hermes during a trip to Germany. That's much more affordable, since shipping cost from Spain can easily equal the cost of the cap. The buyer pays the shipping and an additional €6 as donation to our project.

So far, most caps have reached users in Germany, but some are being sported in Israel, and one will be seen in Holland soon. When we get asked: How do you advertise?, our answer usually is: Our users do outdoor advertising with our caps.

(Updated 18th September 2025)

The Betterbird project receives roughly half its donations from North America and the other half from Europe, predominantly Germany. At first glance, it might seem logical to register Betterbird as a charitable organisation. However, there is no single legal form that works across all jurisdictions: if Betterbird were charitable in Germany, that status would not automatically apply in the United States, and vice versa. A choice would have to be made, leaving half of our donors without tax benefits.

At present, the project has its fiscal residence in Spain (with a sea view). Registering a charitable organisation in Spain is particularly challenging: you need substantial start-up capital and at least three founding members. Even then, the benefits would be limited to the comparatively few Spanish donors, and not extend to those in Germany or elsewhere.

Looking ahead, Betterbird may shift its fiscal residence to Germany. There we have explored several possible structures:

• a registered association (eingetragener Verein, or e.V.)
• a charitable limited liability company (gemeinnützige GmbH, or gGmbH)
• its smaller sibling, the gemeinnützige Unternehmergesellschaft (gUG).

Even the simplest of these, the gUG, comes with hurdles. The administrative overhead is high, especially with many small donations. Some people give as little as €1 per month — which is wonderful support, but from an administrative perspective it means Betterbird would have to track these payments, and issue an official end-of-year tax receipt for €12. Multiply that by hundreds of donors, and you can imagine the paperwork nightmare.

There are also restrictions on how donations can be spent. In Germany, charitable organisations are expected to use the vast majority of funds directly for their charitable purpose. While staff can be paid, salaries must be “reasonable” and proportional to the organisation’s income. In practice, only part of the donations can go to staff salaries — a common benchmark is around 70%. If nearly everything went into the CEO’s pocket, alarm bells would ring with the tax authorities. The remaining funds are supposed to cover infrastructure, contractors, community outreach, or similar costs. For a lean project like Betterbird, that would mean spending donations on things we don’t really need, just to satisfy bureaucracy.

For now, the most practical solution is to keep Betterbird simple: run it as an independent project funded by voluntary donations. That allows us to spend more time improving the software rather than satisfying bureaucracy.

In the long term, if donations grow and the administrative investment makes sense, Betterbird may well adopt a charitable structure in Germany. But today, given the modest level of income, a charitable structure would add more overhead than benefit.

Let’s keep in mind that Thunderbird’s fiscal home, Mozilla’s wholly owned subsidiary MZLA, is a for-profit company. On its donation page, the term “donation” is often replaced by “gift,” for example: Gifts to Thunderbird are not tax-deductible as charitable gifts, but are greatly appreciated!

This article was partly created with the help of AI, however, manual adjustments were made where needed.

We often get asked how many people participate in the project.

Leading the project is Jörg, who served as Thunderbird's first employee as well as maintainer and release engineer from 2016 to 2019. In addition, a seasoned Thunderbird contributor has provided many of the improvements. There are people who send the occasional patch, they are not always visible on GitHub since we commit their work after revision.

Others maintain platform distributions such as Flatpak, Arch Linux, Winget, and Chocolatey, and one volunteer compiles for the ARM processor of Android devices.

We have translators for Czech, Italian, Japanese, Dutch, Polish, Portuguese, Russian, Ukrainian, Swedish and Chinese (listed in alphabetical order by locale code).

We're in personal contact with many of our users who point out bugs, motivate improvements, do testing, and also file upstream bugs on Thunderbird's bug tracker Bugzilla. Sometimes the Thunderbird folks get interested in those bugs and we can include their fixes earlier than they do.

Our project is rather humble, we don't have the many millions the Thunderbird team can rely on. We don't have ~50 staff (amongst them four directors, nine managers, one coordinator and five "specialists"), and we don't have access to the Mozilla server farm used in Mozilla's automation.

Our hardware is rather humble: One Windows build machine, a fast Asus NUC 15 Pro Plus (see picture), and two Mac Minis (Intel + Silicon) for the Mac builds. Linux is compiled in a VM on Windows. This setup makes the project quite flexible; over the years we've shipped releases from three countries on two continents.

Everyone in a while we're looking for new publications about Betterbird. We found this video, which stated the following (quote, 4m22s): It's what Thunderbird could have been if development moved faster and user feedback was (sic) prioritised.

And no, we didn't commission the video and we also don't know the guy and never had contact with him. Also, not all the good claims about Betterbird are true, apart from punctual changes, the performance should be the same as Thunderbird, however, some people start Betterbird on a new profile which may be faster.

In this blog we'll keep you up to date about what's happening in the Betterbird Project. We'll also feature Betterbird features and bug fixes, and rant a bit about the Thunderbird folks.