by George Whittaker The Thunderbird team has officially released Thunderbird 154, delivering several useful new features alongside a substantial collection of fixes for email, calendars, address books, authentication, and stability. Released on August 18, 2026, Thunderbird 154 is now the latest monthly release of the popular open-source email client. For Linux users, one of the most interesting additions is a new optional system tray mode, while Microsoft 365 users gain Microsoft Graph support. The release also improves global search, attachment handling, IMAP reliability, Exchange authentication, and CalDAV synchronization. New Optional System Tray Mode One of Thunderbird 154's most welcome additions is an optional system tray mode. When enabled, closing Thunderbird's last window no longer needs to completely terminate the application. Instead, Thunderbird can remain running in the background through the system tray. This can be particularly useful for users who want Thunderbird avail