Install the new Fedora 18 gpg key
# rpm --import https://fedoraproject.org/static/DE7F38BD.txt
If using SELinux in Enforcing mode
# yum update selinux-policy
Upgrade all packages:
# yum update yum
# yum clean all
# yum --releasever=18 --disableplugin=presto distro-sync
Rebuild rpm database
# rpm --rebuilddb
