Mozilla’s open source Thunderbird email client has been around for a long time, but still only on PCs. Now the organization plans to change this with K-9 Mail, a popular mobile email client that runs on Android. Thunderbird reported this in their blog.

Negotiations between Mozilla and the developers of K-9 Mail began in 2018. Now they have concluded that K-9 Mail will become Thunderbird for Android. The Mozilla team has acquired the K-9 Mail source code and title rights. Project facilitator Christian Ketterer (who goes by cketti in the OSS community) will also join the Thunderbird team “with his valuable expertise and experience on mobile platforms.”

K-9 Mail will remain open source, but Mozilla is investing money and time from developers to improve it. In particular, the application will receive:

  • Setting up an account with automatic Thunderbird settings;
  • Improved folder management;
  • Support for message filters;
  • Sync between the mobile version of Thunderbird and the PC version.

Also, K-9 Mail will be made compatible with the “Thunderbird feature set and appearance”, so the application will be rebranded. The team does not disclose how quickly the changes will take place.

In addition, Mozilla explained why the mobile version of Thunderbird was not created from scratch:

“The Thunderbird team has talked a lot about how we can provide a great mobile experience for our users. After all, we didn’t want to duplicate efforts that could unite them with an open source project that already exists and shares our values. After years of discussing how K-9 and Thunderbird can work together, we’ve decided that it’s best for our users to work together.”

Also, the Thunderbird team invites you to install K-9 Mail to anyone who wants to contribute to the development of the application and provide feedback. However, warns that the program interface will change several times until it becomes final. Thunderbird also states that “they are evaluating the possibility of developing an application for iOS.”