Log Message:
thunderbird: Update to 78.8.1

Changelog:
Fixes
New mail notification did not occur for newly arrived messages if previously
received mail was unread

Directory for saving multiple attachments was not remembered between saves

Opening a message from the command-line using "-mail <URL>" failed

Automatic account setup did not use the provider email and display name

Newly-added identities were not listed in the account manager until it was
closed and reopened

Account provisioner did not properly handle UTF-8 data

Copying a large message to an IMAP server would sometimes prematurely display a
time-out error

OpenPGP: Various errors when importing keys

OpenPGP: Public keys attached to an outgoing email did not have
"Content-Description" set

Address Book: CardDAV sync errors did not retry until Thunderbird was restarted

Calendar: Changing the cache mode of a CalDAV calendar connection would lose
the username of the account

Calendar: Add-on calendars were sometimes not visible after restarting

Calendar: The preview for a recurring task did not use all available space in
the dialog window

Installer: Option to keep distribution directory on upgrade did not work