The message snippets on hover is intentionally removed - it affects accessibility

This doesn't really answer the question though and, if I may be frank, is a really unhelpful answer in general. Is there a setting to get the old functionality back and show the preview of new messages in the popup?

I'd like to point out accessibility isn't a clear-cut thing that has one solution. There are many people with a lot of different disabilities using computers; for them it's important to be able to customize their software to their preferences.

For me, as a visually impaired person, the new version of Thunderbird is a big step in the wrong direction. The contrasts are horrible, the GUI elements are way too condensed and the interface is way too busy and flat overall. I've had to install a theme just to make it somewhat usable for me.

One of the things that also irks me, is the ability to not see what messages there are simply by hovering over an inbox. Now I have to open the inbox, move my focus to another part of the screen, then find out there what the messages are. This makes it less accessible for me.

I'd love to be able to customize more in Thunderbird. And I'm not talking about installing or creating a theme. I'd like to just be able to say "hey, this color blue - I want it darker blue". Or "add some more padding between messages in the inbox". But these are simple features that are very lacking in Thunderbird, without diving into the world of themes.

Generally, Thunderbird is lacking heavily in the accessibility department. The abrupt reply here ('it affects accessibility') kind of says it all. Mozilla is dictacting how the e-mail experience should be for users. That immediately means it's not an accessible piece of software. At least not for everyone.

I 100% agree with @Jan - this change makes the accessibility worse for me. I have multiple accounts in TB, some receiving many emails (reports, etc). Some are important, some not so much. Having to click and change the Inbox to see what's new every time there's a new email makes it really inconvenient and distracting. My previous workflow was to have the Work Inbox open while at work and only occasionally hover over my personal and other secondary Inboxes to see if there's anything new that needs attention. Now I can't do that without completely switching context.

It's really short-sighted to remove established features for reasons as vaguely defined as "accessibility". Make it optional with a switch, make it off by default if needed, but don't remove it without a replacement.

All right, rant over.