#
# source lists for old, archived debian versions
#
# /etc/apt/sources.list
#

# http://archive.debian.org/debian/README:
   squeeze      is Debian  6
   wheezy       is Debian  7
   jessie          is Debian  8
   stretch        is Debian  9

   buster         is Debian 10
   bullseye     is Debian 11
   bookworm is Debian 12

# old debian repositories are here:
# https://archive.debian.org/debian
# https://archive.debian.org/debian-security

# https://wiki.debian.org/SourcesList:
   possible components: main contrib non-free,
                         non-free-firmware for buster and later

# Debian 6 (Squeeze)
  deb http://archive.debian.org/debian squeeze main contrib non-free
  deb http://archive.debian.org/debian-security squeeze/updates main contrib non-free

# Debian 7 (Wheezy):
   deb http://archive.debian.org/debian wheezy main contrib non-free
   deb http://archive.debian.org/debian-security wheezy/updates main contrib non-free
  
# Debian 8 (Jessie):
   deb http://archive.debian.org/debian jessie main contrib non-free
   deb http://archive.debian.org/debian-security jessie/updates main contrib non-free

# Debian 9 (Stretch):
   deb http://archive.debian.org/debian stretch main contrib non-free
   deb http://archive.debian.org/debian-security stretch/updates main contrib non-free

# When updated the sources.list, first reinstall:
   apt-get install dpkg aptitude apt

# to upgrade from version to another use the sequence
   apt-get update
   apt-get upgrade
   apt-get dist-upgrade


How to upgrade Debian 7 (wheezy) to 10 (buster) safely

# donwload ISOs from debian archive:
https://cdimage.debian.org/mirror/cdimage/archive/

# Debian 10 (Buster)
   deb http://deb.debian.org/debian buster main contrib non-free
   # deb-src http://deb.debian.org/debian buster main contrib non-free
   deb http://deb.debian.org/debian buster-updates main contrib non-free
   # deb-src http://deb.debian.org/debian buster-updates main contrib non-free
   deb http://security.debian.org/debian-security/ buster/updates main contrib non-free
   # deb-src http://security.debian.org/debian-security/ buster/updates main contrib non-free


   deb http://archive.debian.org/debian buster main contrib non-free
   deb http://archive.debian.org/debian-security buster/updates main contrib non-free
   deb http://archive.debian.org/debian buster-backports main contrib non-free

# upgrade from 10 to 11
   apt update
   apt dist-upgrade

# Debian 11 (Bullseye)
   deb http://deb.debian.org/debian bullseye main contrib non-free
   # deb-src http://deb.debian.org/debian bullseye main contrib non-free
   deb http://deb.debian.org/debian bullseye-updates main contrib non-free
   # deb-src http://deb.debian.org/debian bullseye-updates main contrib non-free
   deb http://security.debian.org/debian-security/ bullseye-security main contrib non-free
   # deb-src http://security.debian.org/debian-security/ bullseye-security main contrib non-free

   deb http://deb.debian.org/debian bullseye-backports main contrib non-free
   # deb-src http://deb.debian.org/debian bullseye-backports main contrib non-free

# upgrade from 11 to 12
   apt update
   apt upgrade --without -new-pkgs
   apt full-upgrade

# Debian 12 (Bookworm)
   deb https://ftp.debian.org/debian/ bookworm contrib main non-free non-free-firmware
   # deb-src https://ftp.debian.org/debian/ bookworm contrib main non-free non-free-firmware
   deb https://ftp.debian.org/debian/ bookworm-updates contrib main non-free non-free-firmware
   # deb-src https://ftp.debian.org/debian/ bookworm-updates contrib main non-free non-free-firmware
   deb https://ftp.debian.org/debian/ bookworm-proposed-updates contrib main non-free non-free-firmware
   # deb-src https://ftp.debian.org/debian/ bookworm-proposed-updates contrib main non-free non-free-firmware
   deb https://security.debian.org/debian-security/ bookworm-security contrib main non-free non-free-firmware
   # deb-src https://security.debian.org/debian-security/ bookworm-security contrib main non-free non-free-firmware

   deb https://ftp.debian.org/debian/ bookworm-backports contrib main non-free non-free-firmware
   # deb-src https://ftp.debian.org/debian/ bookworm-backports contrib main non-free non-free-firmware