Mozilla plans ground-up UI redesign for Thunderbird email client this July
"Why does Thunderbird look so old?"
That's one of the most frequently asked questions about Thunderbird, according to Thunderbird Project Design Manager Alessandro Castellani (along with "Is Thunderbird dead?"). And it's one he seeks to answer definitively in a new blog post about Thunderbird's planned 2023 release, codenamed Supernova.
The Supernova release will include an overhaul of Thunderbird's user interface. Castellani didn't share screenshots, but he indicated that the new UI would be "simple and clean" and targeted mostly at new users. For "veteran users," the interface will also be "flexible and adaptable" so that people who prefer the way Thunderbird looks now can "maintain that familiarity they love." Supernova will also include several other big changes, including a redesigned calendar and support for Firefox Sync.