Software Update: Mozilla Thunderbird 78.2.0

The Mozilla Foundation has released version 78.2 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 we find, among other things, a dark mode and other parts of the interface, such as the icons and the screen for composing an email, have been taken care of. 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. An automatic update from 68.x to 78.x is still not possible, but will be possible in a future version. The following changes and improvements have been made in this release:


  • OpenPGP Key generation now disabled when there is no default mail account configured
  • OpenPGP: Encrypt saved drafts when OpenPGP is enabled
  • Twitter search removed
  • Calendar: Event summary dialog is now themeable
  • MailExtensions: Some APIs now use defineLazyPreferenceGetter in order to benefit from caching


  • OpenPGP Key Manager search function did not work
  • OpenPGP Key Properties dialog was sometimes too small
  • OpenPGP: Encrypted email would not send if address contained uppercase characters
  • OpenPGP: “Key ID” column could not be resized in Key Manage
  • OpenPGP: Keys containing invalid UTF-8 strings could not be imported
  • OpenPGP: Enable automatic signing for encrypted messages in additional scenarios
  • Many more OpenPGP bug fixes and improvements
  • IMAP fetch chunk size was always 65536 bytes
  • Attachment corruption could occur when downloading large attachments from an IMAP server that supports chunking
  • IMAP server capabilities were not rechecked after upgrading to SSL/TLS connection
  • Message Composer: Order of attachments could not be modified using drag & drop
  • Composing messages with a “fixed width” font did not work
  • Drag and drop of address book contacts did not work in some situations
  • Address book migration failed when there was a dot in the file name
  • Address book: “Always prefer display name over message header” was always checked when editing a contact
  • Address book performance optimizations
  • Dialog to add a new mail account from “Account Settings” did not open
  • “Select All” (Ctrl+A) in message source did not work until focused with a mouse click
  • Ctrl+scroll wheel not zooming in message reader
  • Setting/changing a signature from a file lost when closing account settings
  • Adaptive Junk Mail settings could not be disabled
  • Message filter dialog fixes: Missing scrollbar, drop-down list not wide enough
  • Various UX and theme improvements

Version number 78.2.0
Release status Final
Operating systems Windows 7, Linux, macOS, Windows 8, Windows 10
Website Mozilla Foundation
License type GPL