The Mozilla Calendar Project released Lightning and Sunbird 0.5 today, a major update to their free, open source calendar extension and calendar client. Lightning and Sunbird 0.5 offer a user interface update, event invitations, printing improvements and better integration with Mozilla Thunderbird.

Lightning and Sunbird 0.5 are immediately available for Windows, Mac, or Linux operating systems in 22 languages as free downloads from the Calendar Project homepage.