Executing apt update in a Debian 8 I get the error
W: Failed to fetch http://ftp.debian.org/debian/dists/wheezy-backports/main/binary-amd64/Packages 404 Not Found [IP: 2001:67c:2564:a119::148:12 80] W: Failed to fetch http://ftp.debian.org/debian/dists/jessie-updates/main/source/Sources 404 Not Found [IP: 2001:41d0:202:100:213:32:5:7 80] W: Failed to fetch http://ftp.debian.org/debian/dists/jessie-updates/main/binary-amd64/Packages 404 Not Found [IP: 2001:41d0:202:100:213:32:5:7 80] W: Failed to fetch http://ftp.debian.org/debian/dists/jessie-backports/main/source/Sources 404 Not Found [IP: 2001:41d0:202:100:213:32:5:7 80] W: Failed to fetch http://ftp.debian.org/debian/dists/jessie-backports/main/binary-amd64/Packages 404 Not Found [IP: 2001:41d0:202:100:213:32:5:7 80] E: Some index files failed to download. They have been ignored, or old ones used instead.