[xyjprc]

I wonder how to upgrade from 18 to 19 smoothly

[giulivo]

actually it boils down to very few steps:

  # rpm --import https://fedoraproject.org/static/FB4B18E6.txt
  # yum update yum
  # yum --releasever=19 distro-sync

also see this: https://fedoraproject.org/wiki/Upgrading_Fedora_using_yum#Fe...

[phxql]

sudo fedup-cli --network 19

See http://fedoraproject.org/wiki/FedUp