deb http://ftp.uk.debian.org/debian jessie main
deb-src http://ftp.uk.debian.org/debian jessie main

deb http://ftp.uk.debian.org/debian stretch main
deb-src http://ftp.uk.debian.org/debian stretch main

deb http://security.debian.org/ stretch/updates main
deb-src http://security.debian.org/ stretch/updates main

# stretch-updates, previously known as 'volatile'
deb http://ftp.uk.debian.org/debian stretch-updates main
deb-src http://ftp.uk.debian.org/debian stretch-updates main