When it comes to catching up with the latest news in the world of email clients, a lot of people still rely on Mozilla’s Thunderbird. While it’s been around for a good long time, as a long-time fan of the app myself, I’m always glad to see new Thunderbird versions come out.

Mozilla Thunderbird is one of the most used email clients out there, with around 43% of all emails being read by people using it. The latest version, Thunderbird 91, has been released to the public and had alot of new features added.

To make it easier for Thunderbird users to discover and install extensions, the new version of the main program (Thunderbird 91) now contains a small section of extensions that are installed by default. The extensions are installed automatically after Thunderbird is installed, and can be managed from this section.

The famous Thunderbird software now has a new version available for download. The open source mail and RSS reader has achieved version 91, matching Firefox in terms of release number. A number of modifications have been made in the new edition. Improved Set-Up Wizard, Better Calendar Support, and Multi-Process Implementation all have the potential to increase speed.

Thunderbird 91 released, here are the changes

Thunderbird is my preferred email program. It’s on every PC I own, and it works with any operating system I use. It’s reliable, has all of the functionality you’ll need, allows add-ons, and includes an RSS reader. I’ve been using it for a long time and have had nothing but good experiences with it.

Since version 80, the Thunderbird team has been working on the new version in the beta channel. Firefox 91 has now been matched to the version number. However, if you were hoping for a fresh user interface, you will be disappointed.

The updated version is presently only available for manual download and installation. The built-in updater will make the latest version of the mail client widely accessible later. The list of new features is extensive.

Thunderbird 91 has a lot of new features.

Features that are new

  • MacOS devices with Apple Silicon CPUs have native support.
  • Thunderbird now defaults to the multi-process (e10s) mode.
  • Support for the Latvian language
  • A new user interface for adding attachments has been developed.
  • Message redirection is enabled.
  • Change the order of accounts in the UI
  • Allow empty CC/BCC rows to be shown in the compose window.
  • When sending a reply to a probable non-existent email address, such as “[email protected],” a warning box appears.
  • When the number of public receivers of a message reaches a certain level, a warning notice appears.
  • Add support for the “X-Unsent: 1” header, which allows you to modify a stored email in a compose window.
  • Non-ASCII characters in recipient addresses should be supported.
  • In the compose window, use the context menu to extend the mail list pills to the recipients list.
  • In the multi-message (thread summary) view, Quick Find is now accessible.
  • Accessing the To/CC/BCC fields in the compose window with keyboard shortcuts
  • Allow folder views to be pinned to the Folder Pane.
  • About:support now has language packs and dictionaries.
  • Thunderbird now includes the PDF.js reader.
  • The “Copy Key Id” option has been introduced to the Key Manager context menu in OpenPGP.
  • OpenPGP: Added a config option to prevent saved drafts from being encrypted.
  • BCC recipients’ mail should be encrypted (with warning that it will expose the recipients in the list of keys)
  • Support for CardDAV address books
  • Based on the user information supplied, CardDAV address books are automatically identified.
  • Outlook Contacts Access; Set ldap 2.servers.outlook.dirType to 3 to enable; note that this option may cause startup delays.
  • Replace any add-ons that have been discontinued or are incompatible.
  • Support for Matrix servers at the beta level (set chat.prpls.prpl-matrix.disable to false)
  • Calendar: Auto-detection of remote calendars is now possible.
  • Calendar: Colors for the calendar and categories are now visible in the selection dropdowns.
  • Calendar: An “Edit” option has been added to the event context menu.
  • Calendar: Allows double-clicking to open.ics files
  • Thunderbird now notifies the operating system that it is capable to opening webcal: URLs
  • In the Import dialog, filter and sort the objects to be imported.
  • When no identification matches the event attendees list, prompt to select the identity of an accepted calendar invite.
  • In calendar event dialogs, support the mid: URL scheme for Related Links.
  • When a GMail account is created, permissions to access the calendar and address book are now asked, so that the calendar and address book may be accessed without having to re-authorize (see notes)
  • Per-calendar and global notification options are available in the calendar (in addition to alerts set in events)
  • Undo/Redo for event and task creation and deletion is supported.


  • “Primary Password” has been renamed from “Master Password.”
  • “Add-ons” has been renamed “Add-ons and Themes,” and “Options” has been renamed “Preferences.”
  • Account setup has been relocated to a new tab.
  • Invalid addresses will show red; mail receivers who are not discovered in any address book will no longer appear in red font.
  • When you click on a previously chosen pill in the recipient list, you may now change the address.
  • The color scheme for the folder pane has been updated with an emphasis on readability.
  • Implementations of the sending backend, the SMTP protocol, and the LDAP protocol have all been rebuilt in Javascript.
  • Only UTF-8 is supported by the sending backend, SMTP, and IMAP protocols.
  • If any receivers are not recognized by the SMTP server, sending a message will now fail.
  • An SMTP server’s error messages are now shown to the user.
  • Controls for UI Customization have been relocated to the View menu.
  • When encryption is not set, the “Advanced Settings” for End-to-End Encryption are now disabled.
  • Support for Movemail has been discontinued.
  • The WeTransfer FileLink service has been deactivated.
  • Updated company policies
  • The user interface for printing has been improved.
  • Instead of searching by left-side match, AutoComplete from LDAP directories now searches by substring.
  • To optimize Thunderbird startup speed, chat modules and custom widgets are now lazy-loaded.
  • “libera.chat” is now the default IRC server for new chat accounts.
  • Image-based emoticons have been replaced by Unicode emoticons in chat.
  • When you open an existing event in the calendar, a summary window now appears.
  • When the server supports CalDAV, use it as the default calendar.


  • On IMAP servers, Thunderbird did not process self-signed certificates correctly.
  • Various problems with non-ASCII and unusual characters in IMAP folder names, particularly on Gmail
  • Drag & drop operations could be disrupted by incoming mail notifications
  • Dragging a folder from one IMAP server to another that isn’t yet authorized fails.
  • Thunderbird would cease downloading messages until it was restarted due to temporary problems from POP3 servers.
  • The UI state of the Favorite Folder view did not persist across Thunderbird restarts.
  • After restarting Thunderbird, saved search virtual folders were lost.
  • When deleting a folder, Thunderbird does not properly notify about all impacted filters.
  • Running filters on a maildir folder manually did not work.
  • After clicking the link to download the remainder of the message, partially downloaded messages shown in a stand-alone window did not refresh.
  • After reading some S/MIME signed emails, the message preview showed an incorrect “Sender” header.
  • After exiting the compose window, certain temporary files generated by the message composer were not immediately deleted.
  • The target folder became useless after archiving messages from an NNTP account.
  • The user-configured style for quoted text was not respected in the compose window.
  • When adding new recipients, the message headers in the compose window ignored manual resizing.
  • New message alerts have received a number of enhancements.
  • After an upgrade, a Thunderbird icon pinned to the Windows taskbar returned to a non-functional placeholder.
  • The recipient pills in the message compose window have been improved in a number of ways.
  • On Mac, the keyboard shortcut for bringing up the Message Security window did not function.
  • In certain message lists, the subject column displayed content from incorrect email headers.
  • Account settings: Some previously entered options were not copied to the Advanced Config window when establishing a new account.
  • In the contacts sidebar, the default address book choice was not respected.
  • Importing an address book from a CSV file does not enable you to map all of the fields.
  • Multi-valued characteristics were not shown in LDAP address books.
  • When attempting to remove an entry from an LDAP-backed address book, users with LDAP admin privileges may be able to delete accounts.
  • When an address book was erased, certain preferences connected to it were not cleared.
  • On Linux, the Ctrl+Shift+F shortcut for Advanced Address Book Search did not function.
  • On the photo tab of an address card, radio buttons could not be chosen.
  • The Windows uninstaller does not consistently delete all of the files associated with Thunderbird.
  • Chat: In the create account wizard, double-clicking an account type did not pick it.
  • The settings for your chat account did not always save as anticipated.
  • The colors of user nicknames were not utilized in chat text.
  • Multiple system messages did not collapse during chat.
  • When viewing an event on the calendar, the reminder information seemed to be changeable.
  • HTML rendering in event descriptions has been restored in the calendar.
  • Calendar: The theme colors were ignored by the toolbar in the invitation details dialog.
  • Updates to several dialogs on the calendar
  • Calendar: The years in event dates were not parsed properly when imported and exported through CSV.
  • Calendar: When you clicked on an event box, it wasn’t always focused.
  • The “New Event” box did not appear when dragging and dropping an ICS file to the Today Pane.
  • In the Today Pane, the flickering effect has been reduced.
  • The time of day indication line on the calendar did not refresh automatically.
  • When editing recurring events on a remote calendar, the location information was not saved.
  • Visually, today was difficult to distinguish in the month/multiweek calendar displays.
  • Columns in the Today Pane could not be resized.
  • The text of a calendar event may appear outside of the event block.
  • The time of the event and the name of the event were not vertically aligned.
  • Event descriptions with lengthy URLs, such as Zoom invitations, now have better formatting.
  • RSVP responses to invites are sometimes sent from the incorrect email address.
  • UI and theme enhancements, with a focus on dark themes.

Thunderbird may be downloaded here.

Thunderbird users should eventually get the update automatically via the built-in update mechanism. To update it manually, select menu > Help > About Thunderbird to open the “About” dialog and initiate the update check. After that, the app should download and install the most recent version available.

You may also manually download the program from the developer’s website:

Thunderbird may be downloaded here.

The release notes may be found here.

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On August 12, 2023, Sergey Tkachenko posted in Software.

Sergey Tkachenko’s Biography

Sergey Tkachenko is a Russian software engineer who founded Winaero in 2011. Sergey writes about everything related to Microsoft, Windows, and popular applications on this site. Telegram, Twitter, and YouTube are all places where you may find him.

It’s been a while since we’ve updated the blog with new content, and we’re very excited to announce the release of Thunderbird 91, which marks the first major update to the newest version of the popular email application. As many of you know, the release of Thunderbird was followed by a minor set of bugs, which has been solved by the release of Thunderbird 91.. Read more about latest thunderbird version and let us know what you think.

This article broadly covered the following related topics:

  • thunderbird 91 release date
  • thunderbird version history
  • thunderbird 78
  • latest thunderbird version
  • thunderbird release schedule
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