I think the only prominent UI change that happened is that the bar that holds the search box, Write button etc is above the tab bar now instead of below. Perso

I think the only prominent UI change that happened is that the bar that holds the search box, Write button etc is above the tab bar now instead of below. Personally, I find it a bit jarring, because contextually, that bar only contains stuff related to mail, but that bar and some stuff on it continues to appear even when I switch to Calendar. Thankfully, some CSS takes care of this. Otherwise, it is a quite nice change. Dark mode now also applies to mail contents as well, which is a great change, though I would like a shortcut to swap to light mode.