so, I updated thunderbird to v.45.
I read that from v.38 lightning would be integrated,to my surprise, there is no calendar anywhere to be reached from the menus, neither at preferences (it should be at preferences, a tab there).
I read lightning should be enabled when building thunderbird, therefore ubuntu's one was no lightning at all?
but, how to I get my calendar working again? compile from sources?!? :(
the other questions about it are too old related to thunderbird version.
btw, here is ubuntu 14.04