Update-manager checks to see whether not the repositories you are using are official Ubuntu mirrors, as listed at https://launchpad.net/ubuntu/+archivemirrors, and disables any that are not. As mirrors come and go this functionality allows users to upgrade from release to release without having to modify their sources.list.
Update-manager checks to see whether not the repositories you are using are official Ubuntu mirrors, as listed at https:/ /launchpad. net/ubuntu/ +archivemirrors, and disables any that are not. As mirrors come and go this functionality allows users to upgrade from release to release without having to modify their sources.list.