Thunderbird 78 has just hit Amber today. The Enigmail extension has been deprecated as the Thunderbird team (and Enigmail dev) have now built PGP encryption directly into Thunderbird itself.
One thing folks may run into is if you have moved your encryption keys off your computer and onto your Librem Key (or any other smartcard, hard token, etc), those will not work out of the box with Thunderbird 78. See here for more info: https://wiki.mozilla.org/Thunderbird:OpenPGP:Smartcards
So everyone at Purism prefers Thunderbird? The UI is dated, and just has always been a turn off to me. I’ve been using Mailspring, but I’m interested what others are thinking about on this.
Thunderbird does seem to work with the most email services.
People at Purism use different email services: Thunderbird, Evolution, Mutt, Geary for some cases.
PGP/GPG support is the hard requirement, and smartcard support for some
I made a post to another thread in the PureOS Forum. It does not help with the Librem Key, but there are a couple of links there that may help with the transition from Enigmail. (I am not enamored with the new implementation.)