Mozilla’s latest version of Thunderbird email has a brand-new interface that finally brings the aging application closer to modern aesthetic standards.
Now, it’s not like it’s going to absolutely wow you. The new look isn’t a dramatic departure from the aging UI. Instead, it’s a subtle tweak that gives Thunderbird a more in-touch feel that is not just more pleasing to look at but easier to use. It’s more efficient and it offers a cleaner default font that renders text so much better (especially on the Linux desktop).
The good news is that the new-look Thunderbird isn’t such a dramatic departure from the old that you’ll have to scramble to get up to speed
You are right pistachio, they are just joking around, It even says in the picture which one is which. IMO they actually did a great job by not changing too much, which would anger a part of the userbase, while still improving and modernizing the layout. And lets not forget about the work they did on the core of thunderbird, rewriting a lot, which gives them the opportunity to introduce new features much more easily in the future.