As you might be knowing, Mozilla Firefox can update itself automatically. If you didn't change the default settings when you installed it, it will be configured to check for updates periodically and install them, so you will always have an up-to-date browser. However, there is no clear indication that an update is available for Firefox until you restart it, so Mozilla has finally added a special badge to indicate that updates are available for Firefox. The update badge is disabled by default. Here is how to enable it.