Release Notes

Thunderbird Desktop

Version 68.4.2 | Released January 24, 2020

Check out the notes below for this version of Thunderbird. As always, you’re encouraged to tell us what you think, or file a bug in Bugzilla.

** Thunderbird version 68.4.2 provides an automatic update from Thunderbird version 60.** If you have installed Lightning, Thunderbird's calendar add-on, it will automatically be updated to match the new version of Thunderbird. Refer to this Calendar troubleshooting article in case of problems.

System Requirements: • Window: Windows 7, Windows Server 2008 R2 or later • Mac: Mac OS X 10.9 or later • Linux: GTK+ 3.4 or higher. Details here.

Please refer to Release Notes for version 68.0 to see the list of improvements and fixed issues.

What’s Changed


Calendar: Task and Event tree colours adjusted for the dark theme

What’s Fixed


Retrieval of S/MIME certificates from LDAP failed


Address-parsing crash on some IMAP servers when preference mail.imap.use_envelope_cmd was set


Incorrect forwarding of HTML messages caused SMTP servers to respond with a timeout


Calendar: Various parts of the calendar UI stopped working when a second Thunderbird window opened

Known Issues


When upgrading from Thunderbird version 60 to version 68, add-ons are not automatically updated during the upgrade process. They will however be updated during the add-on update check. It is of course possible to reinstall compatible add-ons via the Add-ons Manager or via

Learn What’s Next

Thunderbird keeps getting better. Subscribe to our newsletter and follow us on social media to stay informed.