Your Debian `cassandra.sources.list` and RedHat `cassandra.repo` files must be updated to the new repository URLs.
The Debian file is typically at `/etc/apt/sources.list.d/cassandra.sources.list`. The RedHat file is typically at `/etc/yum.repos.d/cassandra.repo`. For Debian the repository is now at https://debian.cassandra.apache.org For RedHat the repository is now at https://redhat.cassandra.apache.org/40x/ These repositories offer past versions as well, so it is easier to pin versions and to roll back. The existing repositories under downloads.apache.org/cassandra/ will be removed without further notice. Reach out if you have any questions or any problems.
