- Much more polished user interface in the calendar views
- Event invitations can be sent and received via iMIP/iTIP
- Working hours are back
- Automatic migration of data in Sunbird 0.2, iCal.app, and Evolution
- Much improved printing functionality
- Better integration into Thunderbird (Printing, Undo/redo, Copy/paste)
- Support for Google Calendar (via Google Calendar Provider extension)
- Vastly improved reliability
- Many performance improvements
- Many usability improvements
NOTE: The Lightning link for OS/2's official version of Thunderbird 2.x (currently 2.0.0.4) is INCORRECT on Mozilla's contributed releases page. It is based on the wrong libc DLL version. The correct link is:
http://releases.mozilla.org/.../os2/lightning-0.5.en-US.os2_libc05.xpi
For the PmW-tb 2.0.0.4 (unofficial) OS/2 release, the link is:
http://releases.mozilla.org/.../os2/lightning-0.5.en-US.os2_libc063.xpi
You can download a calendar holiday file for your country here:
http://www.mozilla.org/projects/calendar/holidays.html
Mozilla's homepage for Lightning:
http://www.mozilla.org/projects/calendar/lightning/
Source: Sander Nyman