Birdtray, a Thunderbird tray icon for Linux (Xorg) and Windows that shows the number of unread emails, has seen a new major release. For the Birdtray 1.7.0 release, the developers have added translation support, the ability to draw a border around the number of unread emails in the tray, a new Birdtray icon, and more.
Birdtray is a Firetray (which has been discontinued) alternative that shows Thunderbird in the tray, with an unread email counter on top of the icon; the tray icon can be set to flash when new email are received. However, unlike Firetray, Birdtray is a standalone application, and not a Thunderbird extension. Other Birdtray features include support for multiple email accounts, it can hide and restore the Thunderbird window (so it closes to the tray), and is highly configurable.