This update for enigmail fixes the following issues:

enigmail was updated to 2.2.4:

* bugfixes and improvements
* translation updates

enigmail 2.2.2

* Enigmail version 2.2.x is a specially modified version, which
only works with Thunderbird 78 and later version. Enigmail 2.2.x
doesn't provide the traditional functionality, rather it exists
to help you migrate your keys and settings to Thunderbird 78.

enigmail 2.1.8:

* Fix "Encrypt to key" action destroys PGP/ MIME signature
* Fix Filter fails silently on Enigmail's "Encrypt to key" action
* Fix Disable autocrypt header on custom sender address
* Fix VKS keyserver with custom port cannot be accesse
* Fix Filter fails silently on Enigmail's "Encrypt to key" action
* Fix Thunderbird dies immediately when sending a signed empty-bodied mail
* Fix Decrypted mail has empty Content-Type in the MIME part

enigmail 2.1.7:

* display information about an upcoming release of Thunderbird 78
* Fix minor rendering problem with Deep Dark theme
* Fix running "Encrypt to key" filter fails silently
* Fix improper Content-Type setting for keyserver upload

enigmail 2.1.6:

* Fix Setup Wizard gets Stuck if Keys in GnuPG available
* Fix Cannot confirm publish GnuPG key on WKS server
* Fix Automatic Key Refresh doesn't work with keys.openpgp.org
* Fix per-recipients rule 'set enigmail rules for' field unable to edit
* Fix File names of attachments are not encrypted