Thunderbird calendar addon Year View is now in "(very) low maintenance mode".

It will not be updated to support TB68 or TB70.
As the readme says, I don't have time, resources and motivation to keep work on this.

I'm not really using this plugin anymore from a while now.
I'm using TB only on my office Mac, where I'm still on TB60 because 90% of the addons I need still doesn't work in a way or another on TB68.

Writing "Year View" was a quite painful experience: overall documentation was too old ad outdated or non existent. And that's only on Thunderbird/XUL side: I had to read and understand Lightning code because I couldn't find any other docs. Most of the code in "Year View" is an edited copy of Lightning code. There are also a number of ugly hacks.

From what I read in Thunderbird docs, if I manage to make this thing run on TB68 I will need to rewrite it anyway to make it run on TB70 (where my needed addons will not run anyway). I'm very sorry, but It's not worth the pain.

If you want a proper year view in calendar in the future, please bugs Lightning devs.