dnf shows no F23 updates

[Ron Yorston]

I installed the F23 beta last week when it first came out.  There were
483MB of updates on 23rd September.  I didn't use it again until today.
I was expecting another bumper load of updates, GNOME 3.18 in particular.

However, 'dnf update' and 'dnf --best update' both report there's nothing
to do.

rpm tells me I have gnome-shell 3.17.92-1.  'dnf update gnome-shell' wants
to update gnome-shell and mutter to 3.18.0-1.  'dnf repolist -v' tells me
I have the following metadata:

updates-testing: using metadata from Tue Sep 29 06:54:57 2015.
   fedora: using metadata from Mon Sep 28 09:56:23 2015.
   updates: using metadata from Thu Jul 16 17:29:26 2015.

Once again dnf leaves me baffled.

Ron