Regaining Lightning Calendar In Thunderbird

I used to rely heavily on 'Lightning' calendar Add-on in Thunderbird for reminders, appointments, etc. It always was available whenver I opened Thunderbird, my mail app.

Now, I've lost it. If I try to add it, I get an error message, 'Incompatible with T'bird'.

The problem seems to be, someow I've got onto Beta releases of T'bird. How that hapened, I don't know.

My question is - 'If I uninstall T'bird, then re-istall,

a) will all my files of past mail, contacts list, etc remain or will I lose them (which I cannot risk),
and b) will I then be off the Beta channel updates, and able to re-install a working copy of Lightning calendar?

Thanks

 

You simply need to install the latest general release version of Thunderbird (from a newly downloaded set up file) to get off the Beta Channel, then all your extensions that work with the latest version - 52.2.1 - will now work when installed. Your existing profile data will be picked up with the new install.
You can check you are on the standard release channel after in Tools> Options > Advanced > Update
Download the latest version from here and do a simple install.
https://www.mozilla.org/en-US/thunderbird/

 

You can also install Mozbackup for an additional backup.
http://www.majorgeeks.com/files/details/mozbackup.html

 

Max Turner - Thanks, that is great. I tried to get help from T'bird User Group, but their suggestion was complicated, and didn't work, anyway!

Eldon - Thanks for the suggestion. I don't think I will install that, but thanks for helping