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Thunderbird 91 Available Now

The newest stable release of Thunderbird, version 91, is available for download on our website now. Existing Thunderbird users will be updated to the newest version in the coming weeks.

Thunderbird 91 is our biggest release in years with a ton of new features, bug fixes and polish across the app. This past year had its challenges for the Thunderbird team, our community and our users. But in the midst of a global pandemic, the important role that email plays in our lives became even more obvious. Our team was blown away by the support we received in terms of donations and open source contributions and we extend a big thanks to everyone who helped out Thunderbird in the lead up to this release.

There are a ton of changes in the new Thunderbird, you can see them all in the release notes. In this post we’ll focus on the most notable and visible ones.

Multi-Process Support (Faster Thunderbird)

Thunderbird has gotten faster with multi-process support. The new multi-process Thunderbird takes better advantage of the processor in your computer by splitting up the application into multiple smaller processes instead of running as one large one. That’s a lot of geekspeak to say that Thunderbird 91 will feel like it got a speed boost.

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.

The New Account Setup Wizard

Attachments Pane + Drag-and-Drop Overlay

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).

Compose window with bottom attachment pane.

The new attachment drag-and-drop overlay.

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.

The PDF Viewer in Thunderbird 91

UI Density Control

Depending on how you use Thunderbird and 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 the View -> Density in the menu, you can select the UI density for the entire application. Three options are available: compact – which puts everything closer together, normal – the experience you are accustomed to in Thunderbird, and touch – that makes icons bigger and separates elements.

Play around with this new level of control and find what works best for you!

UI density control options

Calendar Sidebar 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, as well as a show/hide icon for easily toggling what calendars are visible. There is also a lock indicator for read-only calendars. Additionally, although not a sidebar improvement, there are now better color accents to highlight the current day in the calendar.

Improved Calendar sidebar

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.

Dark Theme

Other Notable Mentions

You really have to scroll through the release notes as there are a lot of little changes that make Thunderbird 91 feel really polished. Some other notable mentions are: