Betterbird Blog

We've shipped Betterbird 140.8.0esr-bb19 today. Please refer to the Release Notes for full details.

This new release offers four new functions and a fix for an annoying issue. Here are some details:

The add-on Send Later to schedule sending of messages has many users. Its author doesn't test his add-on in Betterbird, instead he publishes this disclaimer (quote):

Send Later is known to have issues with Betterbird
The Send Later add-on is not regularly tested with the Thunderbird fork called Betterbird, and there are known, unresolved issues which may prevent the add-on from functioning as intended. Using Send Later with Betterbird is therefore not recommended.

We're not aware of any issues, other than the ~55 issues the add-on has anyway. But the good news is, delayed sending in the background is now supported in Betterbird, if you set the following two preferences:

mailnews.sendInBackground set to true and mailnews.sendInBackground.DelayMinutes set to the desired delay in minutes. Be aware that if you close Betterbird before all messages are sent, there is currently no warning.

This is not aimed at replacing the add-on completely, it's aimed at providing a "send delay" that users of MS Outlook are used to.

As we detailed in previous posts like this one, we're now signing our Windows binaries with a code-signing certificate from a reputable source.

By popular demand, the 'Search PreferredSearchEngine for "..." ' option is now also available in the context menu in the compose window.

People who have used Thunderbird for a long time will know that for IMAP accounts, messages read on the server with a different client, like a mobile device, were not subjected to message filtering. That was later changed by introducing preference mail.imap.filter_on_new. However, the filter didn't work when it was run after the junk classification. This has now been fixed.

We've shipped Betterbird 140.7.1esr-bb18 today. Please refer to the Release Notes for full details.

The Thunderbird folks are preparing their 140.7.1 release for next Tuesday, 27th January 2026 to fix a vulnerability in an OpenPGP edge case. Due to scheduling constraints, we're already shipping this now.

Since only 13 days have passed since our Release 140.7.0esr-bb17, this release only contains a few items. By popular demand, we're now distinguishing in the Activity Manager now whether messages were downloaded or not by giving the icon a different colour:

We've also advanced 11 bug fixes the Thunderbird folks are not shipping to their ESR users, refer to our opinion about this policy in this prior blog post.

We've shipped Betterbird 140.7.0esr-bb17 today. Please refer to the Release Notes for full details.

Since only 11 days have passed since our Release 140.6.0esr-bb16, this release only contains a few items. By popular demand we implemented a "reveal" button in the primary password and mail password prompts.

We decided to start the New Year with a fresh release of Betterbird 140.6.0esr-bb16. Too many fixes had accumulated since shipping "bb15" at the beginning of December:

• A user alerted us to a defective French localisation. The issue is also present in Thunderbird 140. We made a "spot fix" to include the missing strings.
• A user had asked us to provide a "dark reader" switch for the compose window to work around "back on black" issues.
• By popular demand we've implemented an option to include the event description in the mail body of the scheduling message.
• We're now enabling address book categories for compliant CardDAV servers which support vCard v4.0.
• "Recent Destination" now include a short MRU list on top of the longer alphabetically sorted list.
• By popular demand, filenames can now contain commas with -compose "attachment=..." is used.
• There was a Mozilla editor issue where the "insertion point" (caret) was displayed incorrectly. We're advancing Mozilla's fix since the issue was rather annoying.
• And finally: Embedded SVG images weren't displayed correctly under some circumstances, another puzzling issue.

And there is more, so please refer to the Release Notes for full details.

Update: No release without an issue. This time the localised strings for the new Categories functionality were missing, so all localised versions and language packs had to be replaced. This happened at 20:00 GMT.

We've shipped Betterbird 140.6.0esr-bb15 today. Please refer to the Release Notes for full details.

Update 8th December 2025: We had to replace the entire release with "build2" since advancing the Thunderbird "fix" for an IMAP bug introduced random crashes. On closer inspection, that code change is likely to have undesired effects, including crashes.

We've addressed issues reported by users in the last four weeks and implemented some new features.

First and foremost, to fund the project, when launching this version for the first time, it will open the end-of-year donation drive page in your browser. Unlike Thunderbird, which is constantly nagging, we're asking for donations this way only once a year in December.

A user who is migrating from Postbox motivated some improvements to the search functionality, see this post for details.

Some of the fixed bugs that were related to searching, for example we rectified and issue that prevented encrypted S/MIME messages to be indexed; a feature introduced in Betterbird 115.

Miscellaneous fixes include missing localisations, where the program talked about Thunderbird instead of Betterbird, and a fix for the much-dreaded "phantom menus" mentioned here. Users of "attachments on top" in the compose window can now reduce the height of the addressing header when many files are attached.

We've shipped Betterbird 140.5.0esr-bb14 today. Please refer to the Release Notes for full details.

We've addressed issues reported by users in the last four weeks.

The Betterbird-native new mail alert on wrong monitor issue is finally fixed, and preference mail.notification.show_on_app_screen should also be working now. We revived preference mail.folderpane.sumSubfolders which had become a victim of Supernova-Kaboom in Thunderbird 115.

Users of the Proton Mail Bridge can now unsubscribe from the likely unwanted so-called "no-select" folders Labels and Folders after setting preference mail.imap.allow_unsubscribe_noselect.

The pesky calendar scroll issue when switching tabs was also fixed by advancing a Mozilla patch. We're also advancing eight bug fixes which are not shipping in Thunderbird 140 ESR yet. As far as providing recent bug fixes to ESR users is concerned, Betterbird is about 50 fixes ahead of Thunderbird.

Finally, the "Recent Destinations" menu was returned to its original state of only showing folders to which messages had been recently moved, the sort order is now based on latest use.

We've shipped Betterbird 140.4.0esr-bb13 today. Please refer to the Release Notes for the full details.

Once again, we've addressed issues reported by users in the last two weeks.

One user wrote to us that they wanted to get more information about the path of a folder, so we added a tooltip to the message list header. The Thunderbird folks jumped onto the bandwagon, dusted off an ancient bug from 2007, and added a tooltip in the folder pane as well. But of course the improvement is already available for Betterbird users while at Thunderbird, they're still thinking about it.

One request about suppressing an unnecessary prompt when opening a link in the compose window came is so late, that half the release had already left the station. So apologies to the Mac users who will have to wait for the next release. But then, most users might not know the feature in the first place or are not too bothered to answer the additional prompt.

Of course the Betterbird-native new mail alert on wrong monitor issue, which had crept into the previous release, was fixed as well. UPDATE: That was wishful thinking, yet again, we had to prepare a "latest build" one day after the release to really fix it. Here it is in English and German.

Detaching an attachment didn't work since the beginning of the 140 series months ago, and only one user noticed?

Finally, it's worth mentioning that when saving a message using its subject as file name, the same file name sanitation is now applied on all platforms. Trigger was a user report that Windows volumes mounted on Linux need the Windows rules applied, not the Linux rules.

In this post we talked about the mishaps which have been common when preparing Thunderbird ESR releases, and version 140.4.0 ESR is no different. Not PhotoShop'ed, you can see it here. The red B's mean that the build failed. Sure, the Thunderbird folks will have another go to get it going, but this is this is already the second attempt, here is the first.

UPDATE: After fixing what is called "build bustage", they got the release built, but they made three mistakes, here listed in declining order of severity:

1. They are not using the correct changeset of the Mozilla base software. For version 140, Mozilla did another "build 2" to plug a security vulnerability.
2. One patch was backported incorrectly.
3. Finally, they pushed all the patches separately, hence increasing the server usage and CO₂ footprint.

But who cares about correctness as long as the donation money is flowing in.

After the preparations described in an earlier post, we've shipped Betterbird 140.3.1esr-bb12 today. Please refer to the Release Notes for the full details.

This release contains a lot of fixes for issues raised by our users in the last two weeks. The upstream Thunderbird release 140.3.1 also contains more fixes than usual. Six of those fixes had already shipped in Betterbird earlier.

Update a few hours later: There is no release without some sort of issue. We just got a report that native new mail alerts, so not system alerts, are displayed at the right corner of the right monitor in a dual-monitor when before they are displayed at the right corner of the left monitor.

Here's what happened: As stated in the Release Notes, we tried to mitigate random flashing of Betterbird-native new mail alert in top left corner of the screen. So after creating the window, we now move it "off-screen", but it may end up on a monitor to the right and finally at its corner. A picture says more than 1000 words: Some users may work around the issue by setting the preference mail.notification.show_on_app_screen. If you're affected, please let us know and we'll provide a solution.

Or you can try the latest build for Windows in English. Yes, how ironic, a "latest build" on the day of the release.

The Thunderbird folks are somewhat unpredictable. For 140.3.0 they made their build on a Thursday to be release on Tuesday the following week. Today is Saturday, and they haven't done 140.3.1 yet which is due on Tuesday. Well, "due" is in the eye of the beholder, looks like the old "volunteer spirit" before 2020 with the motto "Ship when ready" is still alive, even with ~50 paid staff and a multi-million dollar turnover. Likely they'll do it on Monday in a hurry. They're already earmarked 12 bugs for backport to ESR 140, but the backport hasn't happened yet.

Meanwhile we've added more fixes to Betterbird, which will ship in 140.3.1, and which are already available in the "latest build" versions for users who want to try them out early. As always, the Release Notes have the full detail. Amongst the goodies, we're fixing a couple of regressions: disappearing linebreaks when editing mailcites, and OWL default accounts losing their default status. We're also brushing off a fix to the "Junk" button whose context sensitivity was lost in the 2023 Supernova-Kaboom. The Thunderbird folks walked away from a 95% complete solution in February 2025.