Some index files failed to download, they have been ignored, or old ones used instead.

"apt-get update" has been working without incident for months.

A few days ago this message is being reported:

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/edgy-security/universe/binary-i386/Packages.gz 404 Not Found
E: Some index files failed to download, they have been ignored, or old ones used instead.

I examined the URL location. Indeed, there is no such directory. There is a "hardy-security" directory.

There are hardy lines in /etc/apt/sources.list:
deb http://security.ubuntu.com/ubuntu hardy-security main restricted multiverse
deb-src http://security.ubuntu.com/ubuntu hardy-security main restricted

Since the system is configured with 8.04, Hardy, can the "edgy-security" entries simply be removed? Is this a valid fix?

Description: Ubuntu 8.04.1
Release: 8.04

apt:
  Installed: 0.7.9ubuntu17
  Candidate: 0.7.9ubuntu17
  Version table:
 *** 0.7.9ubuntu17 0
        500 http://us.archive.ubuntu.com hardy/main Packages
        100 /var/lib/dpkg/status