Changes

Thunderbird no longer uses the external GnuPG software. Previously, all your own keys and the keys of other people were managed by GnuPG, and Enigmail offered you to view, use and manage them. Now that Thunderbird uses a different technology, it's necessary to perform a migration of your existing keys from GnuPG into Thunderbird's own storage (inside the Thunderbird profile directory). Thunderbird will uses its own copy of the keys, sharing your keys between Thunderbird 78 and GnuPG currently isn't supported. (TODOException: explain the smartcard situationThere is an [[Thunderbird:OpenPGP:Smartcards | optional mechanism to use GnuPG with smartcards]]. It's disabled by default and needs more testing.)