Thunderbird 138.0

Access all your messages, calendars, and contacts in one fast app. Filter and organize the way you like. Manage all accounts separately or in a unified inbox. Thunderbird simply makes your life simple

Razvan Serea News Reporter Neowin · Apr 29, 2025 12:12 EDT

Thunderbird

Thunderbird is a free, open-source, cross-platform application for managing email and news feeds. It is a local (rather than a web-based) email application that is powerful yet easy-to-use.

Thunderbird is clean and elegant by default, but easily customizable to match your workflow and visual preferences. It is loaded with unique and powerful features.

Thunderbird is developed, tested, translated and supported by the folks at Mozilla Corporation and by a group of dedicated volunteers. Thunderbird gives you control and ownership over your email. There are lots of add-ons available for Thunderbird that enable you to extend and customize your email experience.

Thunderbird gives you IMAP/POP support, a built-in RSS reader, support for HTML mail, powerful quick search, saved search folders, advanced message filtering, message grouping, labels, return receipts, smart address book LDAP address completion, import tools, and the ability to manage multiple e-mail and newsgroup accounts.

Thunderbird 138.0 release notes:

What’s New

New mail alert now includes message disposition buttons
New mail notification customization added to macOS Settings

What’s Changed

Changed color override defaults with high contrast mode on macOS and Linux

What’s Fixed

macOS notifications displayed two logos
Message preview truncation in notifications improved
Wrong day of week displayed for some emails
In dark mode with light theme, message reader still displayed in dark mode
Message link and text colors were incorrect when using Dark Reader
Unchecking "Show all headers" in Message Header Settings closed dialog
Address book did not match users when case differed in some instances
Menu items to manage folders were not disabled in offline mode
Using Delete column in "Search Messages..." window could delete other messages
Ctrl or Shift selecting multiple messages reset when dragging across a message
Newsgroups could no longer be re-ordered in the folder tree via drag and drop
Windows users with non-ASCII folder names and profile paths could not view emails
OpenPGP key was not updated when accepted key was reimported with new identities
Dual signed (PGP and S/MIME) emails were not displayed
Notification duration preference enabled when system notifications were enabled
Thunderbird could crash when adaptive message filtering was enabled
CardDAV synchronization to Zimbra server failed
Keyboard navigation was not possible when first header button was disabled
Folders missing from view when "Show only subscribed folders" was not selected
Nickserv messages appeared during successful authentication
Global indexing failed when processing email with invalid calendar data
Clicking a mid: link in Calendar opened two copies of the message
Some calendar requests were blocked due to opaque response blocking
Visual and UX improvements
Security fixes