Software Update: Mozilla Thunderbird 78.9.0

The Mozilla Foundation has released version 78.9 of Thunderbird. Thunderbird is an open source client for e-mail and newsgroups, with features such as support for various mail and news accounts, a spam filter, spell checker and a customizable appearance. In version 78, a dark mode has been added and other parts of the interface, such as the icons and the screen for composing an email, have also been overhauled. Furthermore, the Lightning calendar add-on is now a standard part of the program, there is a new wizard for the first use and only MailExtensions add-ons are supported. The changelog for this release looks like this:


  • New mail notification displayed old messages that were unread
  • Spaces following soft line breaks in messages using quoted-printable and format=flowed were incorrectly encoded; existing messages which were previously incorrectly encoded may now display with some words not separated by a space
  • Some fields were unreadable in the Dark theme in the General preferences panel
  • Sending a message containing an anchor tag with an invalid data URI failed
  • When switching tabs, input focus was not moved to the new tab
  • Address Book: Syncing a read-only Google address book via CardDAV failed
  • Address Book: Importing VCards with non-ascii characters would fail
  • Address Book: Some values ​​may not have been parsed when syncing from Google address books.
  • Add-ons Manager did not show if an addon used experiment APIs
  • Calendar: Removing a recurring task was not possible
  • Various security fixes

Version number 78.9.0
Release status Final
Operating systems Windows 7, Linux, macOS, Windows 8, Windows 10
Website Mozilla Foundation
License type Freeware