You'll also need to install the corresponding version of Lightning.

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

Look for 'Development Channel' at the bottom of the page.

The add-on were installed, I disable and install again bat the sam also in the new calendar, I can't do anything on it, don't let me write something

What version of Lightning do you have installed?

lightning-2.6.5-sm+tb-windows.xpi

Wrong version, you need Lightning 3.2b1.

Did you read and understand the comment above?

Look for 'Development Channel' at the bottom of the page.

Christ1 I recent install Lightning 3.2b1, when I restart Thunderbird, happen that calendar and task works, bat empty So I copy again old profiles form last version (24.5.0), and restart, once more calendar and task don’t work, you can see it bat don’t use it thanks a lot for your soon help

He Christ luckily I was able to retrieve the calendar, installing the old version It was a very frustrating experience that reminded me of early DOS times, over 30 years ago, that under any mistake could lose any amount of files since years I use the beta version of Mozilla (Nightly), and I wanted to experiment with Thunderbird beta, this forces me to reconsider continuing with Mozilla

The beta should only be used by people who know what they are doing. For a production environment use the release version of both, Thunderbird and Lightning, and you won't run into problems like this.

For testing beta's, create a separate profile.

In any case, create regular backups of your profile folder(s).

If you want to move on - good luck.

thanks Christ I use beta, I always prefer, above from 10 years is a meaning to help the software creators one question more, Mozilla for android? regards juan

Mozilla for android?

Not likely to happen.

once again thank you very much, I am preparing a report, possibly serve someone else, Greetings

Make sure that before making any changes you run a full backup using MozBackup. You can get it from http://mozbackup.jasnapaka.com/ That way, should anything happen, you can just go back to the way it was before.