Thunderbird 143.0

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 · Sep 17, 2025 03:34 EDT with 0 comments

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 143.0 fixes:

Web pages with bad certificates displayed as blank
Users could no longer send using smtp-relay.gmail.com
Changing to new drafts folder and then back did not correctly restore the folder
Option did not exist to create new address book under File -> New
Some folders showed new mail count prior to receiving mail
Menu bar was hidden after updating from 128esr to 140esr
Menu Bar -> View contained duplicate accelerator keys
Warning was not logged if mail.openpgp.alias_rules_file file did not exist
Cmd+Shift+F no longer invoked "Search Messages" on macOS
Arrow key selection in global search bar skipped every other result
Drag-drop of unselected contact inserted wrong or no email address
Thunderbird could crash on startup
Adding an account could fail and cause UI hang
Thunderbird could crash when importing mail
Windows new message notification click did not bring Thunderbird to foreground
Delete or detach attachments did not work for some IMAP servers
Saving a new draft retained superceded version
Language field in settings was empty after restart in Troubleshoot Mode
Visual and UX improvements
Security fixes