Thunderbird has native support for GPG via the EnigMail extension: https://support.mozilla.org/en-US/kb...pting-messages

Version 78 and later have built-in support for encryption. I believe only 20.10 (Groovy Gorilla) includes a version of TBird as recent as 78. My 20.04 installation has version 68.10.0 and would require using the EnigMail add-on to Thunderbird. https://blog.thunderbird.net/2019/10...l-and-openpgp/