Fans of the Thunderbird email client will be eager to go hands-on with the latest release, which is now available for download.

So what’s new?

Quite a lot, based on the sheer length of the official Thunderbird 91 release notes!

And it seems that this release is such a major upgrade that users of Thunderbird 78 —you’re not misreading; that is the preceding version number— can not upgrade directly to the new build, not yet anyhow.

A future release will re-enable in-place upgrades to allow users to upgrade Thunderbird 78 to 91. But for now, those who want to try the latest features (and there are a lot of them) need to download Thunderbird 91 directly.

Keen to know more? I bet! So let’s look at this release’s highlights.

Thunderbird 91 features & changes

Thunderbird 91 runs in multi-process mode by default, a feature that’s been a long time coming. While it keeps email in a single process, and other features like the integrated calendar in separate ones. Multi-process should result in a performance boost too.

Thunderbird’s set-up wizard has a new look and a number of new features, plus a location: you now set-up and connect accounts in a new tab rather than yet-another floating window/dialog (which is something Thunderbird is infamous for).

a screenshot of thunderbird 91 's new email set up flow
Thunderbird 91 has a new account set-up wizard

Cute new illustrations (like the octopus above), updated contextual information/labels, and colourful signposting throughout the set-up process make it a more enjoyable, engaging experience.

The account setup wizard is also able to detect and set up CalDAV calendars and address book during setup.

This update to the open-source email app is said to make composing email a touch easier, with a new user interface for adding attachments, an option to show empty CC/BCC rows in compose window, and new keyboard shortcuts to navigate the To/CC/BCC fields.

A warning popup now appears when you try to reply to a (assumed) defunct email address, and when the number of public recipients to a message exceeds the allowed amount.

screenshot of thunderbird 91 calendar
Thunderbird 91 improves calendaring

A clutch of enhancements to Thunderbird’s built-in calendar feature (yes, it has one these days) also features. This includes remote calendar auto-detection, handling of .ics files, registering as a handler for webcal: URLs, and showing a handy colour-coded category dropdown when creating new events.

If you’re a big user of the Thunderbird’s calendar capabilities, chances are you’re going to love all of these rich, productivity-minded changes.

Y’know which change I’m most excited for? The ability to change the order of mail accounts in mail sidebar (albeit not from the sidebar itself but the accounts UI, using drag and drop). I’d gotten into a habit of adding my email accounts in a specific order so that the one I want to show at the top, shows at the top. Now I don’t need to.

Some other new features or notable changes you can find in Thunderbird 91:

  • Pinning folder views to the Folder Pane
  • PDF.js viewer support
  • Beta-level support for Matrix servers
  • Improved colour scheme

Download Thunderbird 91

You can download Thunderbird 91 for Windows, macOS, and Linux from the official Thunderbird website later today (August 12) BUT you skip the wait and grab the release build from from the Mozilla FTP right now (which is where I snagged my copy from).

Will this update be back ported to Ubuntu LTS versions? I don’t know, is the short answer! I will say that if stability is absolutely essential you’re probably best waiting it out with Thunderbird 78 for now anyway as the latest release is fairly substantial and there could be a few bugs that slipped through the net.

However, you can download Thunderbird 91 for Linux to try it out. As the download is a standalone binary (not a traditional installer) you can run both apps side-by-side — literally (though not advised)!

a screenshot showing thunderbird 78 running beside thunderbird 91
You can run Thunderbird 78 and 91 side by side

Just remember that settings you change in one build won’t affect the other, and you’ll have to set-up all of your mail accounts again.

I primarily use email in a browser tab save for the occasional article (like this). This makes it hard for me to properly appreciate how much of an impact these changes will have on those who use the software religiously. So let me know what you think about these changes down in the comments.

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