Upgrade from 13.04 to 13.10: “No new release found” [closed]

I am trying to upgrade from 13.04 to 13.10 following the instructions given in https://help.ubuntu.com/community/SaucyUpgrades:

1)

sudo apt-get install update-manager-core

Output:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
update-manager-core is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.

2)

do-release-upgrade

Output:

Checking for a new Ubuntu release
No new release found

Many people have similar problems with upgrades for other versions. The most mentioned solutions I found are 1) to change from
Prompt=lts to Prompt=Normal in /etc/update-manager/release-upgrades
and 2) to do the release upgrade as a normal user instead of root user. Non of these worked for me.

Any idea to solve my problem?

Thank you.

Answer

Attribution
Source : Link , Question Author : Mencia , Answer Author : Community