My Gnus didn't show that warning message. Why? Because I had
gnus-read-active-file set to
nil. Reading the Gnus
it abundantly clear that the default
'some is superior to
nil, so I
changed to that.
The error is because those servers don't support "LIST NEWSGROUPS". It turns out that I never implemented "LIST NEWSGROUPS" in Feedbase and Lantern - because I had configured Gnus in a way so it didn't issue it in the first place!
Ok, good, now I have an answer: I only get those messages for my email servers.
With the changed configuration of
gnus-read-active-file Gnus now
issues a "LIST NEWSGROUP" at start-up and displays descriptions in the
*Group* buffer. I actually don't want to see the descriptions, so I
gnus-group-line-format to not include
%D. This also has
the nice side effect that "LIST NEWSGROUPS" is no longer issued at
start-up and the warning isn't shown for the (remaining) servers that
don't support it. So now I also have a suggestion on how to avoid the warning.