Latest version of Thunderbird released

Thunderbird 150.0.2​

Security fixes

Thunderbird 151.0​

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

What’s 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
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

I notice the updates come close to the Firefox updates as well. Almost synchronized, almost...

Thunderbird 151.0.1​

Fixed​

Forwarding/Redirecting Exchange messages failed with NS_ERROR_OUT_OF_MEMORY

This latest version broke dark themes...

Josey Wales said:

Thunderbird Eclipse 152.0

Click to expand...

Version 152.0 | Released June 16, 2026​

What's New ​

SecurityDevices enabled in enterprise policies

One-click account setup for Thundermail accounts

What’s Changed​

Use 'Add' instead of 'New' for account, calendar, address book creation buttons
GMail OAuth updated to use PKCE
Mail server hostname 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

What’s 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

Thunderbird 152.0.1 Released June 30, 2026​

Fixed​

Reply All button was missing for some EWS messages with multiple recipients

Security fixes

Thunderbird 153.0 Final

What’s New
Unified folders now display account color indicator with account name tooltip
OAuth login for mail accounts now opens in default web browser
Thundermail services can now be used without installing an add-on
OAuth responses now verify issuer fields and reject missing required issuers

What’s Changed
Removed Odnoklassniki chat setup and directed users to XMPP configuration

What’s Fixed

Ctrl+S did not save PDF attachments opened in Thunderbird tabs
TLS errors incorrectly reported all unknown failures as untrusted certificates
Thunderbird could crash during shutdown
Thunderbird could crash when copying an empty list of messages
New mail alerts incorrectly sized or positioned on some multi-monitor setups
Old IMAP profile migration deleted INBOX and other mailbox files
Space bar did not scroll in PDF attachments opened from emails
'Search Messages' shortcut (Ctrl+Shift+F) failed in standalone message window
Folder location widget used non-localised name
Empty confirmation dialog when more messages opened in tabs than mailnews.open_tab_warning
Removing tags from IMAP messages could fail and tags reappeared after refresh
Folder pane could not be horizontally resized in additional 3-pane tabs
Global search failed to display inaccessible messages found in local folders
Numeric subfolders were sorted alphabetically instead of naturally
Virtual folder folder-picker showed unlabeled IM account as selectable folder
Virtual folders failed to preserve the online search setting
Apple Mail OpenPGP emails failed to decrypt due to hidden recipient key ID
OpenPGP import of public key with experimental packets failed with unclear error
Performance issue when decrypting encrypted messages
Opening messages with OpenPGP keys was slow and blocked the UI for large keyrings
OpenPGP key refresh failed when fingerprint lookup returned multiple results
Invalid S/MIME encryption certificate caused misleading send errors
Esc cleared quick filter pin after changing folder
Dragging email address between compose windows failed to add recipients
Thunderbird could crash when using Find and Replace All
Sending Message dialog got stuck on "Filter complete." after successful send
Compose with PDF attachments opened PDFs instead of creating a new email
Attachments opened via -compose on Windows could use incorrect filenames
Ctrl+Enter opened attachment instead of sending the message
Compose window remained open when delayed sending was enabled
Account hub showed connection security instead of actual authentication method
Account Hub GSSAPI autoconfiguration incorrectly prompted for a password
New identity dialog lacked reply-matching and end-to-end encryption settings
Account Hub manual EWS setup lacked OAuth authentication option
Thunderbird could fail to shut down cleanly during active OAuth requests
Account Hub kept OAuth selected after changing to hostname without OAuth support
Account Hub showed a false error when returning from EWS manual configuration
Account Hub autodetect wrongly prompted for a password when auth was unavailable
QR exports with SMTP passwords generated invalid data for Thunderbird for Android
Message Filters 'Run Now' button remained disabled after filter run or mail check
Redirected CardDAV URLs resolved relative URLs against the wrong host
Thunderbird could crash when completing folder copy/move
Forwarding some Apple Mail messages incorrectly attached inline text as a file
Auto-compaction could corrupt database and cause crashes during syncs
NNTP server with invalid TLS certificate could not be added to certificate exceptions
Sent message in EWS account showed message as unread in the sent items folder
EWS NTLM authentication triggered login failures despite successful syncs
Saving inline Exchange images used incorrect filenames and file types
Cancelled message send could not be retried and hung with SMTP timeout errors
EWS folders failed to show new mail notifications until the folder was selected
Corrupted NNTP account data caused excessive memory use and startup crash
Multiple selected IMAP folders could not be moved or deleted together
Non-Latin IMAP keywords were lowercased and encoded incorrectly as MUTF-7
Message tags were lost when moving folder from local folder to IMAP folder
Reply All button was missing for some EWS messages with multiple recipients
EWS users could not permanently delete individual Trash messages
Removing a chat account threw an exception and failed to clear the UI
Primary Password policy was detected but not enforced for saved account passwords
Copying one recurring event occurrence failed to set the date when pasted
Calendar invites were incorrectly marked processed after calendar sync completed
ICS event comments were not displayed in Thunderbird event details
Visual and UX improvements

Security fixes

Lots of fixes on this last one and I'm using 140.12.1esr (64-bit)

New codename for Thunderbird 153.0 is "Meadow"...