Installing Thunderbird 6.0 on Ubuntu/Linux Mint via PPA repo

The latest version of Thunderbird has the following changes:

• Thunderbird is based on the new Mozilla Gecko 6 engine
• Several theme improvements for Windows 7
• Support for Windows 7 Jump lists
• Several fixes when importing email from Microsoft Outlook
• Default mail client check now works with newer Linux distributions
• Various other user interface fixes and improvements
• Numerous platform fixes that improve speed, performance, stability and security

The Thunderbird 6.0 PPA Repos:

sudo add-apt-repository ppa:mozillateam/thunderbird-stable
sudo apt-get update

And then Installing it:

sudo apt-get install thunderbird