Mozilla and the Thunderbird email client development team released version 78.2.1 on the fixed channel last night. Existing Thunderbird installations will be automatically upgraded to the new version, provided that the auto-update feature is not turned off and you have the version 78.x.
One of the great new features of Thunderbird 78 was the support for PGP encryption built directly into the application. Thunderbird users used to have to install extensions like Enigmail to have PGP support.
The release of Thunderbird 78 had built-in support for OpenPGP, but was not enabled by default due to some issues that needed to be resolved.
The release of Thunderbird 78.2.1 allows OpenPGP support by default in Thunderbird. Choose Tools> OpenPGP Key Manager, and you'll see available keys that were previously created or imported, and options for creating new keys that can be used to encrypt your chats via email.
Clicking Generate> New Key Pair starts the process. All you have to do is select one of your available email accounts and click on "create key" to create an encryption key.