machines behind apt-proxy do not see 8.04 upgrade

[stan]

I have a couple of machines that use apt-proxy to get their updates. I have
updated the machine that provides apt-proxy services to these machine, but
update manager on them still does not see that the 8.04 upgrade is
available.

What can I do to fix this?

-- 
One of the main causes of the fall of the roman empire was that, lacking
zero, they had no way to indicate successful termination of their C
programs.