Software Update: Mozilla Thunderbird 91.0.3

The Mozilla Foundation has released an update to version 91 of Thunderbird for the third time in a short time. Thunderbird is an open source email and newsgroup client, with features such as support for several mail and news accounts, a spam filter, spell checker, and a customizable look and feel. In version 91 has included a warning when an email is sent to a possibly non-existent address, or when there are too many addresses on the public address line. There is also support for CardDAV and there is a native client for a Mac equipped with an Apple Silicon processor.

At the moment it is not yet possible to do an automatic update from version 78 to 91. An existing installation can be updated by manually downloading and running the installation file. The automatic migration will be added in a future version. In version 91.0.3, the following changes and improvements have also been made:

Fixes

• Folder icons could be overridden by linked favicons in HTML messages
• Unified folders showed no messages when underlying folders were removed
• Folder pane toolbar did not always persist after restarting Thunderbird
• Compose window attachment pane did not close when disabling signing of an OpenPGP message
• Using “Reply to List” with some list emails incorrectly opened a “no-reply” warning
• Unread message count badge on Windows tray icon did not update after moving messages to the Junk folder
• Account setup UX issues with Exchange autodiscover
• Account settings did not display non-UTF-8 server descriptions correctly
• Thunderbird sometimes sent an unnecessary “SMTPUTF8”, causing some servers to reject mail
• No mouseover pop was displayed with event details for non-all-day events in the Today Pane
• Filtering tasks in the Today Pane did not work
• Email based event scheduling displayed the date and time in a format unreadable by humans