Linux (Ubuntu): installing php-mysql : WARNING: The following packages cannot be authenticated!

Trabla: Linux (Ubuntu): installing php-mysql : WARNING: The following packages cannot be authenticated!

I catch this problem trying to install PrestaShop 1.6 on old Ubuntu 13.10


sudo apt-get install php5-mysql
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-3.11.0-15 linux-headers-3.11.0-15-generic linux-image-3.11.0-15-generic
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libapache2-mod-php5 php5-cli php5-common php5-curl php5-gd php5-intl php5-pgsql php5-readline php5-xmlrpc
Suggested packages:
  php-pear php5-user-cache
The following NEW packages will be installed:
  php5-mysql
The following packages will be upgraded:
  libapache2-mod-php5 php5-cli php5-common php5-curl php5-gd php5-intl php5-pgsql php5-readline php5-xmlrpc
9 upgraded, 1 newly installed, 0 to remove and 16 not upgraded.
Need to get 141 kB/6,613 kB of archives.
After this operation, 298 kB of additional disk space will be used.
Do you want to continue [Y/n]? y
WARNING: The following packages cannot be authenticated!
  php5-intl php5-readline php5-cli libapache2-mod-php5 php5-xmlrpc php5-gd php5-pgsql php5-curl php5-common php5-mysql
Install these packages without verification [y/N]? y
Err http://us-east-1.ec2.archive.ubuntu.com/ubuntu/ saucy-updates/main php5-xmlrpc amd64 5.5.3+dfsg-1ubuntu2.6
  404  Not Found Err http://security.ubuntu.com/ubuntu/ saucy-security/main php5-xmlrpc amd64 5.5.3+dfsg-1ubuntu2.6
  404  Not Found Err http://security.ubuntu.com/ubuntu/ saucy-security/main php5-gd amd64 5.5.3+dfsg-1ubuntu2.6
  404  Not Found Err http://security.ubuntu.com/ubuntu/ saucy-security/main php5-pgsql amd64 5.5.3+dfsg-1ubuntu2.6
  404  Not Found Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/p/php5/php5-xmlrpc_5.5.3+dfsg-1ubuntu2.6_amd64.deb  404  Not Found Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/p/php5/php5-gd_5.5.3+dfsg-1ubuntu2.6_amd64.deb  404  Not Found
Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/p/php5/php5-pgsql_5.5.3+dfsg-1ubuntu2.6_amd64.deb  404  Not Found 
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

SOLVING:

To solve this problem we need edit file:
/etc/apt/sources.list
and change archive.ubuntu.com and security.ubuntu.com with old-releases.ubuntu.com

To execute this run following commands in terminal:

cd /etc/apt 
sudo cp sources.list sources.list.bak 
sudo sed -i "s/archive./old-releases./g" sources.list 
sudo sed -i "s/\/security./\/old-releases./g" sources.list 
sudo apt-get update

Discussion on superuser.com (StackOverFlow)
http://superuser.com/questions/327472/packages-cant-be-authenticated-during-apt-get-install-on-ubuntu-9-04