Thunderbird Email Client Plans Major Overhaul to Clear Out Ancient Code

The nearly 20-year-old Thunderbird email client will undergo a major overhaul that promises to modernize the interface and make the software more reliable. 

The overhaul aims to cut down on the “technical debt” that the free, open-source email client has accumulated over the past decade from developers tweaking and programming new features.

“Simply ‘adding stuff on top’ of a crumbling architecture is not sustainable, and we can’t keep ignoring it,” Thunderbird Product Design Manager Alessandro Castellani wrote in a blog post(Opens in a new window).

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Castellani likened Thunderbird’s computer code to “an enormous Lego tower” built on top of a center piece in the wrong shape. “If you replace just that piece, the whole tower will crumble. This means you have to slowly remove the blocks above it to keep the tower from collapsing,” he wrote. “Then, once you reach that center piece, you replace it, and then add back the pieces you removed with slightly different pieces.”

Hence, the Thunderbird team is preparing a “massive rework from the ground up” to streamline the email client’s underlying software. The overhaul will span three years and involve rewriting ancient code in the software while rebuilding the email client’s interface from scratch.

Existing Thunderbird email client
(Credit: Thunderbird)

The changes will arrive in the upcoming Thunderbird 115 “Supernova” release slated for July 2023. Users can expect the new version to offer “a simple and clean interface for ‘new’ users, as well as the implementation of more customizable options with a flexible and adaptable interface to allow veteran users to maintain that familiarity they love,” Castellani said. 

“Improvements to the UI and UX (user interface and user experience) will continue for the next 2 years, with the objective of creating an interface that can adapt to everyone’s needs,” he added. 

‘You Can’t Make Everyone Happy’

That said, the coming changes may rankle some Thunderbird users. “We try to balance what we know is needed with what our users and external contributors want. But you can’t make everyone happy; trying to do so can actually dilute and devalue your product,” Castellani noted.

Thunderbird still technically runs under Firefox’s developer Mozilla Foundation. However, a decade ago, Mozilla shifted its priorities away from the email client in favor of letting users maintain Thunderbird’s development. This led millions of active users and developers to contribute code to software. However, the volunteers’ efforts also created a disjointed and inconsistent user experience for the email client, Castellani said. 

From 2017 to 2020, Mozilla oversaw Thunderbird through a subsidiary that has since used paid employees to steer the email client’s development. But in those years, the Thunderbird team alienated many past contributors, Castellani said. In response, the Thunderbird team plans to approach the overhaul with an “open and ethical process” that’ll also look at feedback from users. 

“We always listen and incorporate the feedback from the community, and we try to balance what we know is needed with what our users and external contributors want,” he added.