All you need to do is to run following commands to update Fedora to the latest version.
#install wget
yum install wget -y
#download latest fedora repos
wget ftp://download.fedora.redhat.com/pub/fedora/linux/releases/13/Everything/i386/os/Packages/fedora-release-13-1.noarch.rpm
#import gpg-key
rpm --import ftp://download.fedora.redhat.com/pub/fedora/linux/releases/13/Everything/i386/os/RPM-GPG-KEY-fedora-i386
#install rpmlibs dependency. Require to install fedora-release-13
yum install rpm-libs -y
#upgrade fedora release
rpm -Uvh fedora-release-13-1.noarch.rpm
#upgrade fedora destro
yum upgrade -y
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