Lightning, Sunbird & Timezone definitions for Mozilla Calendar has been updated (2016/07/18). Download these files from:
https://bitbucket.org/dryeo/dry-comm-esr31/downloads/
"Make Thunderbird or Seamonkey even more powerful with the fully integrated Lightning Calendar. Lightning allows you to organize your schedule, access remote calendars and much more."
By Dave Yeo
Source: eCSoft/2