Lighning is a Extension for Thunderbird and SeaMonkey.

https://addons.mozilla.org/en-US/thunderbird/addon/lightning/versions/

I tried the last 2 versions that should install on Firefox 29.0 from the list and still got the same error that I noted on my question. (ie: Lightning NOT compatible with Firefox 29.0..... I am using Ubuntu 14.04 and am completely up to date with updates, but Lightning still will NOT install as it has error of "Not Compatible with v29.0")

-- HELP -- I that see others are having the same problem also.

In that link I posted it says Works with SeaMonkey and Thunderbird. If it worked with Firefox also (which no version has) then it would be mentioned also.

Are you actually trying to install it in Firefox on purpose when it will never work or are you trying to get this installed in Thunderbird?

For Thunderbird you need to right-click and save this extension to disk and then install it in Thunderbird.

These are what the Lightning extension works with

• http://www.seamonkey-project.org/
• http://www.mozilla.org/en-US/thunderbird/

The Lightning calendar works with the email in Thunderbird and email client in the SeaMonkey suite. Firefox however is only a web browser. http://www.mozilla.org/en-US/projects/calendar/

I apologize James. I was thinking Thunderbird and writing Firefox. I guess my brain went off somewhere else yesterday. It installed fine when I re-read your reply again and followed your instructions. Thank you so much. I got several others installed too that really improved Thunderbird the way I wanted it to appear. Thanks again for that counsel.