
Judging from the team's openness regarding development, it appears that they want to strike the right balance between modernizing the interface and making sure that users have choice when it comes to it.Ī recently published video by Castellani on YouTube highlights how this may look like. Now, after nearly six years, the team is ready to deliver an optimized email client, and the first major step is the launch of the modern, consistent interface. Thunderbird is developed and maintained by employees of MZLA Technologies. This changed when MZLA Technologies was formed, a subsidiary of Mozilla Foundation. One of the outcomes of the community-drive approach to development was that the user interface was inconsistent. It turned out as well that long-term success and sustainability was not guaranteed at that time. While that meant a growing community and keeping Thunderbird alive, it also meant that coordination was challenging.

Thunderbird development suddenly peaked as new supporters and contributors contributed to the project.

Back in 2012, Mozilla announced that it would hand over Thunderbird to the community to turn it into a community-driven model. Mozilla developed Thunderbird next to Firefox for almost the first then years of the email client's existence. Things break regularly because of the many changes that Mozilla makes on a daily basis, and while these apply to development builds of Thunderbird for the most part, dealing with them binds resources. If Mozilla's massive army of developers makes changes to the code, Thunderbird's much smaller team needs to review these to make sure that they don't affect functionality in the client. The project benefits from its Firefox code significantly, as it gets features such as cross-platform support, a web renderer, JavaScript compiler, security fixes or extensions system automatically from it.ĭependence on Firefox comes at a cost, however, as Thunderbird relies heavily on Firefox code. Castellani explains in a blog post that Thunderbird is practically "a bunch of code running on top of Firefox". The tower is still standing, but it is difficult to replace parts that are no longer needed or need modernization. Product design manager Alessandro Castellani compared Thunderbird's current base to an "old, fragile LEGO tower". The dedicated team wants to improve Thunderbird in three main areas in the coming three years, beginning with this one: modernize the aging code base of the free email client, create an interface redesign, and start to release new versions of the email client on a monthly basis, similar to Firefox's release schedule.

The small team of developers plans to release Thunderbird 115, codename Supernova, in July 2023.
