In a business environment, people who switch from Microsoft Outlook to Mozilla Thunderbird often miss having the calendar/task features in Outlook. Fortunately, you can add Calendar and Task functionality to Thunderbird with the Lightning add-on.
- Go to the Lightning download page
- Right click on the download link and Save As… (If you don’t, Firefox might try to install the add-on itself.)
- Open up Thunderbird and click on Tools > Add-ons
- Install the Lightning file you just downloaded
- Once you’re done, restart Thunderbird, and start using your new Calendar feature!
- If you need Holiday calendars, you can get them here