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Thunderbird for Android / K-9 Mail: May 2024 Progress Report

11 responses

Welcome reader! This is the place where we, the Thunderbird for Android team, inform you about what we worked on in May 2024.

We’ve been publishing monthly progress reports for quite a while now. If you haven’t subscribed to the RSS feed yet, now would be a good time to start. You can even use your favorite desktop app to do so – see Thunderbird + RSS: How To Bring Your Favorite Content To The Inbox.

And if you need a reminder on where we left off last month, head over to April’s progress report.

Material 3

The most noticeable development effort going on right now is the conversion of the user interface to the design system Material 3. You can follow our progress by becoming a beta tester and installing the K-9 Mail 6.9xx beta versions.

The first step consisted of changing the theme to Material 3. That changes things like the style of buttons and dialogs. 

Next, we replaced the many icons used throughout the app. But when using the beta version we — and some of you — noticed that not all of the new icons are a good fit. So we’ll update those icons in the next design iteration.

One of the main reasons for switching to Material 3 is the ability to support dynamic colors. It will allow the app to (optionally) use the system color scheme e.g. derived from the wallpaper. But in order for this to work properly, we need to update many places in the app that currently use fixed theme colors. This is an ongoing effort.

Targeting Android 14

As mentioned in April’s progress report, we’ve included the changes necessary to target Android 14 in the latest beta versions. So far we haven’t seen any crashes or bug reports related to these changes. So we plan to include them in the next maintenance release – K-9 Mail 6.804.

F-Droid metadata (part 3)

Unfortunately, this topic was part of the last two progress reports. So we’re very happy to report that the app description is now finally available again on our F-Droid app listing.

Other things we’ve worked on

Developer documentation

We’ve done some work on making our developer documentation more accessible. There’s now a table of contents and we have the capability to render it to HTML using mdbook. However, we haven’t set up automatic publishing yet. Until that happens, the documentation can be browsed on GitHub: K-9 Mail developer documentation.

Small IMAP improvements

We took some time to have a closer look at the communication between the app and the server when using the IMAP protocol and noticed a few places where the app could be more efficient. We’ve started addressing some of these inefficiencies. The result is that K-9 Mail can now perform some action with fewer network packets going back and forth between the app and the server.

Support for predictive back

Google is working on improving the user experience of the back gesture in Android. This effort is called predictive back. The idea is to reveal (part of) the screen to which a successful back gesture will navigate while the swipe gesture is still in progress.

In order for this to work properly, apps that currently intercept the back button/gesture will have to make some changes. We’ve started making the necessary modifications. But it’s still a work in progress.

Community Contributions

GitHub user Silas217209 added support for mailto: URIs on NFC tags (#7804). This was a feature a user requested in April.

Thank you for the contribution! ❤️


In May 2024 we published the following stable release:

… and the following beta versions:

Thanks for reading, testing, and participating. We’ll see you next month!

11 responses

Freddie Ybert wrote on

Would be nice to add HTML signature support in K-9 mail


Jason Evangelho wrote on

Thanks Freddie, we’re hearing this request frequently and will pass it on to the Android team.


John Lasson wrote on

Would be great to get the overview page back.


Mohammad S. wrote on

Thanks for the update and all the work you do to provide this awesome software for us to use.


Rick Berns wrote on

Great work, thank you! Are you considering bringing the overview page back?


David Nenders wrote on

Awesome! Thanks for all the work you are doing and to offer this great app.
Only thing I’m really missing is an overview page instead or beside the unified inbox.


Sven Palmgren wrote on

When will K-9 Mail be renamed to Thunderbird?
Can I read all mail both in my computer and my mobil phone regardles of where I wrote them?


Jason Evangelho wrote on

When the team, alongside our newly hired mobile release manager, determine that K-9 Mail has the right amount of features and polish, we’ll convert it to Thunderbird for Android. We should have a better idea of what the timeline looks like in the coming weeks.


Devin wrote on

I’m a huge fan of this email client. Unfortunately, I have to resort to using Evolution because the extension for handling my work Office 365 account on Thunderbird is feature lacking. I’d like to have full sync of all my tasks, emails and calendar for Office 365 accounts on Thunderbird. I won’t hesitate to move over to thunderbird once that support is there. I’ve been using K9 for my Android phone and I love it!


Jason Evangelho wrote on

Good news, Devin: our first stage of native Exchange support will land in Thunderbird 128 (it may be in a point release later in August or September). This will comprise only email support, but we intend to keep working diligently on full support. You can track the progress in our Monthly Dev Digests here:


Franck wrote on

Marvellous! Thank you very much!!!
Greetings to all members of the team


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