Thunderbird 3.1.3 and Thunderbird 3.0.7 updates are now available for Windows, Mac, and Linux for free download from www.GetThunderbird.com. These releases make several improvements to Thunderbird’s security and product stability.
As part of Mozilla Messaging’s ongoing security and stability update process, we strongly recommend that all Thunderbird users upgrade to these releases. If you already have Thunderbird 3.1 or 3.0, you will receive an automated update notification within 24 to 48 hours. You can also manually fetch this update by selecting "Check for Updates…" from the Help menu.