New in Thunderbird 91

This article describes some of the major changes visible to users in Thunderbird version 91. Full details of all the changes can be found in the Thunderbird release notes from 91.0 and up.

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Screenshot of Thunderbird's new system dark mode.
Screenshot of Thunderbird's new account setup wizard.

New Account Setup

One of the most noticeable changes for Thunderbird 91 is the new account setup wizard. The new wizard not only features a better look, but does auto-discovery of calendars and address books and allows most users to set them up with just a click. After setting up an account, the wizard also points users at additional (optional) things to do – such as adding a signature or setting up end-to-end encryption.

Attachments & Drag-and-Drop

The attachments pane has been moved to the bottom of the compose window for better visibility of filenames as well as being able to see many at once. We’ve also added an overlay that appears when you drag-and-drop a file into the compose window asking how you would like to handle the file in that email (such as putting a picture in-line in your message or simply attaching it to the email).

Screenshot of Thunderbird's new attachment overlay.
Screenshot of the new UI density options in Thunderbird.

UI Density Control

Whether you are using it on a large desktop monitor or a small laptop touchscreen, you may want the icons and text of the interface to be larger and more spread out or very compact. In Thunderbird 91, under View -> Density in the menu, you can select the UI density for the entire application. Three options are available: compact (small), normal(medium), and touch(large).

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Protect Your Privacy

Whether it’s work or play, you deserve to have privacy when you are online. A VPN, Virtual Private Network, can help you create a secure, private connection to the internet. So that when you are traveling, connecting to WiFi, or simply want more online security - you know that your information is protected from prying eyes.

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Screenshot of the new options in the Thunderbird calendar sidebar.

Calendar Improvements

Managing multiple calendars has been made easier with the calendar sidebar improvements in this release. There is a quick enable button for disabled calendars, a lock indicator for read-only calendars, and a show/hide icon for easily toggling what calendars are visible. Outside the sidebar, there are now better color accents to highlight the current day in the calendar.

Better Dark Theme

Thunderbird’s Dark Theme got even better in this release. In the past some windows and dialogues looked a bit out of place if you had Thunderbird’s dark theme selected. Now almost every dialogue and window in Thunderbird is fully styled to respect the user’s color scheme preferences.

Screenshot showing the new dark theme in Thunderbird.
Screenshot of new PDF viewer in Thunderbird.

PDF Viewer

Thunderbird now has a built-in PDF viewer, which means you can read and even do some editing on PDFs sent to you as attachments. You can do all this without ever leaving Thunderbird, allowing you to return to your inbox without missing a beat.

Other Notable Changes

There are many other big changes that make Thunderbird 91 a very large release including:

  • Native support for macOS devices built with Apple Silicon CPU
  • CardDAV Address Book Support (and CardDAV auto-detection support)
  • Printing UI updated
  • Ability to change order of accounts in UI
  • Registers to handle .ics files, letting you preview and import events to the calendar by double clicking the file

You can see details of all our changes in the release notes for Thunderbird 91.0 and up.

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Thunderbird is both free and freedom respecting, but we’re also completely funded by donations! Help us sustain the project and continue to improve.

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