Thunderbird 154

Thunderbird 154 is the August monthly release of Mozilla’s email client, and it finally addresses a complaint that has followed the application for most of its existence. We covered the release in more detail when it shipped.

System tray mode

Closing Thunderbird’s last window no longer has to terminate the application. With the optional system tray mode enabled, the client keeps running in the background and stays reachable from the tray.

This matters because of how mail notifications work. Thunderbird can only tell you about new mail if it is running, and for years the only way to keep it running was to leave a window open. Users who wanted background mail checking without a window on screen reached for extensions, and extensions that hook window management have historically been the first thing to break on a major version bump.

Having it built in removes that fragility. It is opt-in, so nothing changes unless you enable it.

Microsoft Graph

Thunderbird 154 enables Microsoft Graph for Microsoft 365 accounts. Graph is Microsoft’s API platform for accessing Microsoft 365 services, and using it rather than legacy protocols matters as Microsoft continues restricting what it permits over basic authentication and older interfaces.

Support is currently limited to email. Calendar is not supported yet, which is worth knowing before migrating a work account expecting full parity.

Attachments and search

There is a new “Copy To” folder context menu for message/rfc822 attachments, and you can drag those attachments directly into the folder tree. If you regularly deal with forwarded messages as attachments, this removes a save-then-import round trip.

Global search picks up the option to open results in list view by default.

Installing

# Flatpak
flatpak install flathub org.mozilla.Thunderbird

# Debian and Ubuntu
sudo apt update && sudo apt install thunderbird

# Fedora
sudo dnf install thunderbird

# Arch
sudo pacman -S thunderbird

Distribution packaging lags upstream by varying amounts. The Flatpak and Mozilla’s own tarball are the fastest routes if you want it immediately.

Release cadence

Thunderbird moved to monthly releases some time ago and has signalled the pace is increasing further. Version numbers climb quickly as a result, so the jump from 153 to 154 represents a month of work rather than anything dramatic.

Verify Your Download

Mozilla publishes SHA-256 checksums and detached GPG signatures alongside each release in the archive directory.