Upgrade Debian release 7.11 (wheezy) to 8.5 (jessie)

I have a Debian system (virtual development box, not reachable from the internet) which has not been updated for a while. Now I'd like to make up for this, but it seems the sources are not available any more:

$ sudo -s
> LANG=C apt-get update
...
Ign http://backports.debian.org squeeze-backports/non-free Translation-de_DE
Err http://backports.debian.org squeeze-backports/main amd64 Packages
  301  Moved Permanently [IP: 128.31.0.62 80]
Err http://backports.debian.org squeeze-backports/contrib amd64 Packages
  301  Moved Permanently [IP: 128.31.0.62 80]
Err http://backports.debian.org squeeze-backports/non-free amd64 Packages
  301  Moved Permanently [IP: 128.31.0.62 80]
Fetched 13.5 kB in 8s (1512 B/s)
W: Failed to fetch http://backports.debian.org/debian-backports/dists/squeeze-backports/main/binary-amd64/Packages  301  Moved Permanently [IP: 128.31.0.62 80]

W: Failed to fetch http://backports.debian.org/debian-backports/dists/squeeze-backports/contrib/binary-amd64/Packages  301  Moved Permanently [IP: 128.31.0.62 80]

W: Failed to fetch http://backports.debian.org/debian-backports/dists/squeeze-backports/non-free/binary-amd64/Packages  301  Moved Permanently [IP: 128.31.0.62 80]

E: Some index files failed to download. They have been ignored, or old ones used instead.

I was able to dist-upgrade from 7.4 to 7.11 today, but this seems to be all I can get.

Is there a way to successfully update and dist-upgrade my system to Debian 8, Jessie? My main goal is to get apache 2.4 that way.

Update: Here is my /etc/apt/sources.list file, empty and commented-out lines removed:

deb http://debian.uni-duisburg-essen.de/debian/ wheezy main
deb-src http://debian.uni-duisburg-essen.de/debian/ wheezy main
deb http://security.debian.org/ wheezy/updates main
deb-src http://security.debian.org/ wheezy/updates main
deb http://debian.uni-duisburg-essen.de/debian/ wheezy-updates main
deb-src http://debian.uni-duisburg-essen.de/debian/ wheezy-updates main
deb http://opensource.wandisco.com/debian wheezy svn18

Solution 1:

Upgrading to Debian 8 Jessie is more complicated than simply running dist-upgrade. I’ll summarise the steps involved but I’d strongly suggest that you fully familiarise yourself with Upgrades from Debian 7 (wheezy) from the Release Notes for Debian 8 (jessie).

1. Configure the package repositories.

   You modify the configuration file for package repositories, /etc/apt/sources.list to include the URLs for the repositories for Jessie. It should include entries similar to:

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

   See Preparing sources for APT

2. Get the list of available packages for Jessie:

   apt-get update
   

3. Ensure you have enough disk space to download all the new packages. Then, upgrade the packages which can be upgraded without requiring any other packages to be removed or installed:

   apt-get upgrade
   

   This should have carried out a minimal upgrade which installs a new kernel and udev.

4. Reboot the system to use the new kernel.

5. Complete the process by upgrading the remaining packages:

   apt-get dist-upgrade