Thunderbird Updates & Release Notes
13 updates curated from 1 source by the Releasebot Team. Last updated: Jun 16, 2026
- Jun 16, 2026
- Date parsed from source:Jun 16, 2026
- First seen by Releasebot:Jun 16, 2026
Thunderbird 152.0
Thunderbird adds enterprise policy security device support, one-click Thundermail setup, and a broad round of mail and calendar fixes plus performance, OAuth, MIME, and usability improvements.
What’s New
SecurityDevices enabled in enterprise policies
One-click account setup for Thundermail accounts
Changed
Use 'Add' instead of 'New' for account, calendar, address book creation buttons
GMail OAuth updated to use PKCE
Hostname of mail server is also checked when detecting address books and calendars
Updated about:rights to replace local with hosted url
'Hide completed tasks' now also hides cancelled tasks
Fixed
New mail alerts appeared on wrong monitor in three-monitor setup
Spam messages triggered new mail notifications before being moved to Spam folder
Filtered IMAP or NNTP subscriptions were lost after closing Subscribe dialog
'Download Headers' dialog for newsgroups failed to open
Messages nested deeper than 255 levels disappeared from threading view
Performing Delete followed by Undo on thread parent message could corrupt view
Single messages still appeared collapsible after thread members were deleted
Updated threads remained misordered until folder refresh or resort
Non-threaded subject sorting separated 'RE:' replies from original messages
BCC recipients were included in signed email headers
Performance issue when decrypting encrypted messages
Filter search on Body missed draft messages containing German umlauts
Thunderbird could crash during local message search
Blocked file warning showed without 'Unblock File' button in compose window
Forwarding/Redirecting Exchange messages failed with NS_ERROR_OUT_OF_MEMORY
Compose window closed early and send progress dialog hung after NNTP failure
Compose window stayed open after sending when mailnews.sendInBackground set
Microsoft OAuth2 failed when HTTPS localhost redirect was not intercepted
Pasting contact photos stopped working when photo button had focus
Filter dialog lacked focus ring and had poorly distinguishable buttons
Subfolder kept stale accessibility unread count after unread messages were deleted
'Edit as New Message' and inline 'Forward' not possible with PGP-signed messages
Various MIME improvements
EWS messages could go missing from folder view
IMAP "Show only subscribed folders" could not be changed without restart
Unable to delete more than 1000 messages at a time on Microsoft 365
EWS folders in Trash were moved to Trash again instead of being hard deleted
IMAP notifications repeated for emails read on another device after sleep wake
POP3 deadlocked when server went silent without closing socket
Calendar acceptance no longer distinguished between single occurrence and series
Transparent popups on macOS made calendar event editing difficult
Duplicate attendees were added to invitations instead of being filtered out
Task percentage complete was not preserved separately from status in tooltips
Visual and UX improvements
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - May 26, 2026
- Date parsed from source:May 26, 2026
- First seen by Releasebot:May 27, 2026
Thunderbird 151.0.1
Thunderbird fixes Forwarding and Redirecting Exchange messages that failed with NS_ERROR_OUT_OF_MEMORY.
Fixed
Forwarding/Redirecting Exchange messages failed with NS_ERROR_OUT_OF_MEMORY
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source All of your release notes in one feed
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- May 19, 2026
- Date parsed from source:May 19, 2026
- First seen by Releasebot:May 16, 2026
- Modified by Releasebot:May 19, 2026
Thunderbird 151.0
Thunderbird ships a broad update with Thundermail OAuth sign-in, better Account Hub and EWS setup, task sorting and calendar fixes, plus reliability and security improvements. This release also improves message handling, search, IMAP, OpenPGP, and accessibility.
What’s New
- Enable Thundermail OAuth sign-in with account auto-configuration
- Enable users to override OAuth provider details for EWS accounts
- Tasks can be sorted by created or modified date
Changed
- Reinstated default application check when Thunderbird starts
- OpenPGP public key no longer attached by default in signed-only messages
Fixed
- Thunderbird could crash when processing message headers
- Thunderbird could crash on startup
- Calendar view tabs were not properly keyboard accessible
- Thunderbird could crash when processing new incoming messages
- On macOS, dragging attachments out of Thunderbird created multiple copies
- Cancelling a newsgroup posting was not possible
- Some IMAP emails showed current time instead of correct received date
- Search result count was missing when using 'Find in Message' or Ctrl+F
- Search results showed older irrelevant emails before newer exact matches
- Reply with selected text lost formatting for HTML messages containing </pre>
- Multipart/related attachments were not preserved when editing or forwarding
- Forwarded malformed MIME email had empty body and extra attachment
- OWL add-on description was not visible in Account Hub for non-en-US locales
- Account Hub prompted for password after OAuth login, causing Outlook setup failure
- Auto-discovered Account Hub values were not preserved for manual editing
- Account Hub links for encryption and signature opened the wrong account
- Virtual folders did not update correctly for filtered POP3 messages
- Thunderbird could crash in spam filtering
- Using thunderbird -compose with double quotes made last email address invalid
- With auto-mark-read disabled, large mail still marked as read during load delay
- It was not possible to create date-only all-day tasks
- Task context menu (right-click) had several disabled menu items
- 'Current Tasks' view showed past and finished tasks instead of only unfinished
Visual and UX improvements
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - May 8, 2026
- Date parsed from source:May 8, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 140.10.2esr
Thunderbird fixes security issues and invites users to share feedback or file bugs.
Fixed
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - May 8, 2026
- Date parsed from source:May 8, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 150.0.2
Thunderbird fixes security issues and encourages users to share feedback or file bugs.
Fixed
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - Apr 30, 2026
- Date parsed from source:Apr 30, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 140.10.1esr
Thunderbird fixes security issues in a routine update.
Fixed
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - Apr 30, 2026
- Date parsed from source:Apr 30, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 150.0.1
Thunderbird fixes a crash when processing message headers and includes security fixes.
Fixed
Thunderbird could crash when processing message headers
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - Apr 21, 2026
- Date parsed from source:Apr 21, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 140.10.0esr
Thunderbird fixes newly translated strings and includes security fixes.
Fixed
Newly translated strings were not available in Thunderbird
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - Apr 21, 2026
- Date parsed from source:Apr 21, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 150.0
Thunderbird adds better account setup, OpenPGP and S/MIME search support, touch-friendly calendar scrolling, PDF page reordering, and customizable appearance options. It also brings accessibility, stability, and security fixes across mail, folders, Exchange, and Microsoft Store installs.
What’s New
'Recent Destinations' in General Settings now supports alphabetical sorting
Added support for generating Unobtrusive Signatures (OpenPGP)
Message body search enabled for OpenPGP and S/MIME encrypted messages
Account hub is opened on the first run of Thunderbird
Address book cards can be copied to the clipboard as vCard
Custom Accent Color can be chosen in Appearance Settings
Calendar month/multiweek views are now scrollable with touch screen
PDF pages can be reorganized directly in the PDF viewer
Changed
Flatpak beta app ID changed from org.mozilla.Thunderbird to org.mozilla.thunderbird
Fixed
Unknown command-line arguments passed to Thunderbird did not print warning
Thunderbird could crash when creating a folder
Saved email filenames were not not always cross-platform safe
Compose progress dialog used unlocalised folder name
Clicking on a folder in the folder pane did not always open folder
Could not scroll to message bottom or view all attachments in some cases
Accounts could be listed twice after adding new account
Account Hub manual configuration was missing OAuth2 option
Microsoft Store installs did not open when clicking 'news://' link or .eml file
Folder states were not exposed to screen readers in saved search properties
Mailbox name was not announced and message count was incorrect for screen readers
POP3 could stop downloading mail until restart
Exchange servers/clients caused memory leaks by holding mutual references
Authentication could fail for some exchange accounts
'Move to New Window' option for the calendar was disabled
Calendar view had date and time axes swapped
Visual and UX improvements
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - Apr 7, 2026
- Date parsed from source:Apr 7, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 140.9.1esr
Thunderbird fixes security issues and invites users to share feedback or file bugs.
Fixed
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - Apr 7, 2026
- Date parsed from source:Apr 7, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 149.0.2
Thunderbird fixes security issues in this release.
Fixed
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - Mar 26, 2026
- Date parsed from source:Mar 26, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 149.0.1
Thunderbird reports no changes requiring release notes in this release.
Changed
There are no Thunderbird changes requiring release notes in this release
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source - Mar 24, 2026
- Date parsed from source:Mar 24, 2026
- First seen by Releasebot:May 9, 2026
Thunderbird 140.9.0esr
Thunderbird fixes security issues and encourages users to share feedback or file bugs.
Fixed
Security fixes
As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla
Original source
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Curated by the Releasebot team
Releasebot is an aggregator of official product update announcements from hundreds of software vendors and thousands of sources.
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