I'm sure that a few days ago when I went to Menu -> Plugins -> Download Plugins I was presented with a (hierarchical) list of available plugins to install.

If I do this now the list is empty.

Also, if I try Main menu -> Setup -> Software update I get:

Sorry feeds are down for maintenance, try again later.
I get the same message for things like Main menu -> Setup -> System -> Network -> MiniDLNA setup (and others on that list).

My network is working fine (e.g. imdb queries work OK).

So have the feeds really been down for maintenance for the last few days?
If not, any idea what the problem might be?