what the hell did thunderbird do to lightning calendar

I first noticed that i couldn’t convert an e-mail to an event like i was used to.

Then i found out that was because the whole damn calendar was gone.

Why, Mozilla, why?

After following these instructions - https://support.mozilla.org/en-US/kb/calendar-updates-issues-thunderbird - resetting extensions.installedDistroAddon.{e2fda1a4-762b-4020-b5ad-a41df1933103}

i have a WebExtensions process permanently using 116% of my CPU (out of 1200%, but still).

And, of course, still no calendar.

My Lightning extension was reported as no longer compatible. And there’s no compatible version listed in the extensions search. There is no helpful message on the extension page that it’s been superseded or moved into core.

Even the more markety page - https://www.thunderbird.net/en-US/calendar/ - just offers an ancient version (“Works with Thunderbird 52.0 - 52.*”; i have Thunderbird 60)

Thanks to Chris Thompson for figuring this out, this fixed it:

sudo apt install xul-ext-lightning

Unable to edit https://support.mozilla.org/en-US/kb/calendar-updates-issues-thunderbird because i think Mozilla hates those of us who have had an account for a while, i instead edited https://developer.mozilla.org/en-US/docs/Mozilla/Calendar/Calendar_Versions which i could sign up fresh for with GitHub in 20 seconds (OK, that gives me at least three separate Mozilla accounts, yay)— anyway, i added this note to i hope help others:

Note: After Thunderbird 52, Lightning is built-in rather than obtained through the extensions. If you lose the calendar see calendar update issues and check to install dependencies on your operating system (such as xul-ext-lightning).