Download Thunderbird Donate
featured post title image

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

cketti 0 responses

A new year, a new progress report! Learn what we did in January on our journey to transform K-9 Mail into Thunderbird for Android. If you’re new here or you forgot where we left off last year, check out the previous progress report.

Account setup

In January most of our work went into polishing the user interface and user experience of the new and improved account setup. However, there was still one feature missing that we really wanted to get in there: the ability to configure special folders.

Special folders

K-9 Mail supports the following special folders:

In the distant past, K-9 Mail was simply using common names for these folders and created them on the server if they didn’t exist yet. But some email clients were using different names. And so a user could end up with e.g. multiple folders for sent messages. Of course there was an option to manually change the special folder assignment. But usually people only noticed when it was too late and the new folder already contained a couple of messages. Manually cleaning this up and making sure all email clients are configured to use the same folders is not fun.

To solve this problem, RFC 6154 introduced the SPECIAL-USE IMAP extension. That’s a mechanism to save this special folder mapping on an IMAP server. Having this information on the server means all email clients can simply fetch that mapping and then there should be no disagreement on e.g. which folder is used for sent messages.

Unfortunately, there’s still some email providers that don’t support this extension. There’s also cases where the server supports the feature, but none of the special roles are assigned to any folder. When K-9 Mail added support for the SPECIAL-USE extension, it simply used the data from the server, even if it meant not using any special folders. Unfortunately, that could be even worse than creating new folders, because you might end up e.g. not having a copy of sent messages.

So now the app is displaying a screen to ask the user to assign special folders when setting up an account. 

This screen is skipped if the app receives a full mapping from the server, i.e. all special roles are assigned to a folder. Of course you’ll still be able to change the special folder assignment after the account has been created.

Splitting account options

We split what used to be the account options screen into two different screens: display options and sync options.

Improved server certificate error screen

The screen to display server certificate errors during account setup has received an overhaul.

Polishing the user experience

With the special folders screen done, we’re now feature complete. So we took a step back to look at the whole experience of setting up an account. And we’ve found several areas where we could improve the app. 

Here’s an (incomplete) list of things we’ve changed:

Fixing bugs

Some of the more interesting bugs we fixed in January:

Community Contributions

new-sashok724 fixed a bug that prevented the use of IP addresses for incoming or outgoing servers (#7483).

Thank you ❤️


If you want to help shape Thunderbird for Android, become a beta tester and provide feedback on new features while they are still in development.

0 responses