Thunderbird Desktop
Version 140.3.1esr | Released September 30, 2025
Check out the notes below for this version of Thunderbird. As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla.
For help and a quick start on Thunderbird 140, see Thunderbird 140 Eclipse FAQ
For more on all the new features in Thunderbird 140, see What’s New in Thunderbird 140.
System Requirements: Details
- Windows: Windows 10 or later
- Mac: macOS 10.15 or later
- Linux: GTK+ 3.14 or higher
What’s Fixed
fixed
Certificate viewer tab would not load when opened from exception dialog
fixed
Layout inside a pane could cause performance degradation in other panes
fixed
Thunderbird could crash in various scenarios
fixed
Adding an account could fail and cause UI hang
fixed
Address book items with mixed case email addresses were not recognized
fixed
No way to distinguish between Thunderbird Release/ESR in Windows registry
fixed
Initial launch had long load times and UI lag while messages downloaded
fixed
Sending emails via servers with self-signed certificate did not work
fixed
Opening Website header link in RSS feed incorrectly re-encoded URL parameters
