When starting X-11 using the default GNOME desktop, many icons were missing (replaced with large X’s) and an error about dbus-launch failing to start appeared.
To fix this error, I had to manually install the dbus-x11 package (which the upgrade did not install for some reason): "yum install dbus-x11"
Also, at first startx would fail with a font failure error message. I then remembered I disabled startup of xfs (the X Font Server) a few years ago. I temporarily started xfs with "/sbin/service xfs start" and it was happy.