Following on yesterday’s release of Firefox 16.0, Mozilla has released version 16.0 of the Thunderbird E-mail client, for Windows, Linux, and Mac OS X. The new release contains a number of bug fixes; it also has fixes for 13 security vulnerabilities, 10 of which Mozilla rates as Critical. The new version adds box.com to the services that can be used with FileLink (an alternative to mailing large attachments); it also adds the capability to do silent background software updates, if the user wishes. More information is available in the Release Notes.
Because of its security content, I recommend that you update your systems as soon as you conveniently can. You can get the new version using the built-in update mechanism (Help / About Thunderbird / Check for Updates); alternatively, you can download a complete installation package from Mozilla’s site.