Mozilla has released a new version, 17.0.7, of its Thunderbird E-mail client, for Windows, Linux, and Mac OS X. This release includes fixes for eight identified security vulnerabilities, four of which Mozilla rates as Critical. The Release Notes don’t really have much else to say.
Because of the security content of this release, I recommend that you update your systems as soon as you conveniently can. You can get the new version via the built-in update mechanism, or you can download a complete installation package here.