Thunderbird 148.0

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 · Feb 25, 2026 10:22 EST 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 148.0 changelog:

What’s New

Accessiblity is improved in various tree views
'Favorites' added as destination for 'Move To' and 'File' buttons
Add mail.openpgp.load_untested_gpgme_version to load untested GPGME version
NTLM is exposed as an available authentication method for EWS accounts

What’s Changed

Read folders are now removed from Unread Folders view
Yahoo, AT&T, AOL accounts are switched to PKCE, a more secure auth protocol

What’s Fixed

Periodic new mail checks silently stopped after sleep or network outages
Donation banner stole focus when Thunderbird was running in the background
Status bar messages displayed unlocalizedd folder names or IMAP mailbox names
New Folder dialog allowed invalid folder creation without a selected parent folder
New/unread messages in collapsed thread were not obvious enough
Invalidly signed unencrypted emails were indicated as worse than unsigned ones
Untagged messages were not working correctly with quick filter
Calendar/address book sections were shown in Account Hub when there were none
Shortcuts could be executed on background mail window while in Account Hub
Adding a Gmail account prompted for OAuth during auto config
New password-based Exchange accounts failed to save passwords in login manager
'Move Message to' filter action was not logged
Unknown OAuth providers were not allowed during EWS manual config in AccountHub
Saved search in unified folder resulted in server error
EWS password prompt looped endlessly if the password was empty
Account Hub manual configuration flow for Exchange accounts was incorrect
Google calendars had broken RSVP logic and wrong organizer on new events
CalDAV calendars that invited calendar alias did not give all response options
CalDAV calendar with multiple addresses could crash on multi-attendee invites
iCal imports misread unknown timezones as GMT, creating events at wrong times
Visual and UX improvements
Security fixes