Thunderbird Desktop
Version 91.0 | Released August 11, 2021
Check out the notes below for this version of Thunderbird. As always, you’re encouraged to tell us what you think, or file a bug in Bugzilla.
** Thunderbird version 91.0 is only offered as direct download from thunderbird.net and not as an upgrade from Thunderbird version 78 or earlier.** A future release will provide updates from earlier versions.
System Requirements: Details
- Windows: Windows 7 or later
- macOS: macOS 10.12 or later (macOS 11.0 for Silicon)
- Linux: GTK+ 3.14 or higher
What’s New
new
Native support for macOS devices built with Apple Silicon CPUs
new
Thunderbird now operates in multi-process (e10s) mode by default
new
Latvian language support
new
New user interface for adding attachments
new
Enable redirect of messages
new
Ability to change order of accounts in UI
new
Allow showing empty CC/BCC rows in compose window
new
Warning popup when sending a reply to a likely non-existant email address such as "[email protected]"
new
Warning popup when public recipients of a message exceeds threshold
new
Add support for "X-Unsent: 1" header, to open a saved email in a compose window for editing
new
Add support for non-ASCII characters in recipient addresses
new
Context menu to expand mail list pills in the compose window to the list of recipients
new
Quick Find is now available in the multi-message (thread summary) view
new
Keyboard shortcuts to access To/CC/BCC fields of compose window
new
Allow pinning folder views to the Folder Pane
new
Language packs and dictionaries added to about:support
new
PDF.js viewer now included in Thunderbird
new
OpenPGP: "Copy Key Id" option added to Key Manager context menu
new
OpenPGP: Added config option to disable encrypting saved drafts
new
Encrypt mail to BCC recipients (with warning that it will expose the recipients in the list of keys)
new
CardDAV address book support
new
CardDAV address books automatically detected based on provided user information
new
Access to Outlook Contacts; To enable, set ldap_2.servers.outlook.dirType
to 3
; This setting may cause startup delays.
new
Suggest replacements for discontinued/incompatible add-ons
new
Chat: Beta-level support for Matrix servers (set chat.prpls.prpl-matrix.disable
to false
)
new
Calendar: Remote calendar auto-detection now supported
new
Calendar: Calendar and category colors now displayed in selection dropdowns
new
Calendar: "Edit" item added to event context menu
new
Calendar: Support opening of .ics files by double-click
new
Calendar: Thunderbird now informs the operating system that it knows how to open webcal: URLs
new
Calendar: Filter and sort items to be imported in the Import dialog
new
Prompt to choose the identity of an accepted calendar invite when no identity matches the event attendees list
new
Support mid: URL scheme for Related Links in calendar event dialogs
new
Permissions to access calendar and address book are now requested when a GMail account is set up, so that calendar and address book can be accessed without having to re-authorize (see notes)
new
Calendar: Per-calendar and global notification settings (in addition to alerts set in events)
new
Tasks: Undo/Redo support for event and task creation and deletion
What’s Changed
changed
"Master Password" renamed to "Primary Password"
changed
Renamed "Add-ons" to "Add-ons and Themes" and "Options" to "Preferences"
changed
Account setup moved to a tab
changed
Mail recipients that are not found in any address book will no longer appear in red type; invalid addresses will appear red
changed
Clicking on an already-selected pill in the recipient list will now allow editing the address
changed
Folder pane color scheme overhauled with a focus on readability
changed
Sending backend, SMTP protocol, and LDAP protocol implementations rewritten in Javascript
changed
Sending backend, SMTP, and IMAP protocols now operate only in UTF-8 mode
changed
Sending a message will now fail if any recipients are not accepted by the SMTP server
changed
Error messages from an SMTP server are now displayed to the user
changed
UI Customization controls moved to the View menu
changed
End-to-End Encryption "Advanced Settings" are now disabled when encryption is not configured
changed
Movemail support removed
changed
WeTransfer FileLink provider removed
changed
Enterprise policies updated
changed
Printing UI updated
changed
AutoComplete from LDAP directories now searches by substring instead of left-side match
changed
Support dropped for macOS address book integration
changed
Chat modules and custom widgets are now lazy-loaded to improve Thunderbird startup time
changed
Default IRC server for new chat accounts changed to "libera.chat"
changed
Chat: Image based emoticons replaced with Unicode
changed
Calendar: Opening an existing event now opens summary dialog
changed
Calendar: Default to CalDAV when supported by the server
What’s Fixed
fixed
Thunderbird did not properly handle Self-signed certificates on IMAP servers
fixed
Various issues with special and non-ASCII characters in IMAP folders names, especially on Gmail
fixed
Drag & drop operations could be disrupted by incoming mail notifications
fixed
Dragging a folder from an authenticated IMAP server to a not-yet authenticated server fails
fixed
Temporary errors from POP3 servers would cause Thunderbird to stop downloading mail until it was restarted
fixed
Favorite Folder view did not maintain UI state between Thunderbird restarts
fixed
Saved search virtual folders were not retained after restarting Thunderbird
fixed
Thunderbird did not correctly warn about all affected filters when removing a folder
fixed
Manually running filters on a maildir folder did not work
fixed
Partially downloaded messages displayed in a stand-alone window did not refresh after clicking link to download the rest of the message
fixed
An erroneous "Sender" header was displayed in the message preview after viewing certain S/MIME signed emails
fixed
Some temporary files created by the message composer were not automatically removed after closing the compose window
fixed
Archiving messages from an NNTP account made the target folder unusable
fixed
Compose window: The user-configured style for quoted text was not honored
fixed
Message headers in compose window disregarded manual resizing when adding additional recipients
fixed
Various improvements to new message notifications
fixed
A Thunderbird icon pinned to the Windows taskbar reverted to a non-functional placeholder after an update
fixed
Various improvements to recipient pills in message compose window
fixed
Keyboard shortcut to open the Message Security popup did not work on Mac
fixed
Subject column in message lists sometimes showed text from invalid email headers
fixed
Account settings: When creating a new account, some already entered settings did not copy to the Advanced Config dialog
fixed
Default address book preference was not honored in the contacts sidebar
fixed
Import Address Book from CSV did not not allow mapping all available fields
fixed
LDAP address books did not display multi-valued attributes
fixed
Address Book: Users with LDAP admin rights could delete accounts if trying to delete an entry from an address book backed by LDAP
fixed
Some preferences related to an address book were not removed when the address book was deleted
fixed
Shortcut for Advanced Address Book Search (Ctrl+Shift+F) did not work on Linux
fixed
Radio buttons could not be selected on photo tab of an address card
fixed
Windows uninstaller did not always remove all Thunderbird program files
fixed
Chat: Double clicking an account type in new account wizard did not select it
fixed
Chat account settings did not always save as expected
fixed
User nickname colors were not used in chat content
fixed
Chat: Multiple system messages did not collapse
fixed
Calendar: Reminder details appeared editable when viewing an event
fixed
Calendar: HTML rendering in event descriptions restored
fixed
Calendar: The toolbar in the invitation details dialog was not honoring the theme colors
fixed
Calendar: Various dialog updates
fixed
Calendar: Import and export via CSV did not parse years correctly in event dates
fixed
Calendar: Event boxes were not always focused when clicked
fixed
Dragging and dropping an ICS file to the Today Pane did not populate the "New Event" dialog
fixed
Calendar: Reduced flickering effect in Today Pane
fixed
Calendar: The time of day indicator line did not update automatically
fixed
Location field was not preserved when modifying recurring events stored on a remote calendar
fixed
Today was difficult to pick out visually in the month/multiweek calendar views
fixed
Columns in Today Pane were not resizable
fixed
Calendar event text could render outside the confines of the event block
fixed
Event time and event name were not vertically aligned
fixed
Improved formatting of event descriptions with long links, such as Zoom invites
fixed
RSVP replies to invitations sometimes sent from the wrong email address
fixed
Various UI and theme improvements, especially to dark themes
fixed
Various security fixes
Known Issues
unresolved
OTR chat encryption fails on 32-bit Windows builds