Upgrading F29 -> F30

First, make sure your Fedora 29 is updated:

  # dnf upgrade --refresh

Then, be sure you have installed the dnf-plugin-system-upgrade:

  # dnf install 'dnf-command(system-upgrade)'

Start the system upgrade download with DNF:

  # dnf system-upgrade download --releasever=30

Reboot and upgrade.

Once the previous command finishes downloading all of the upgrades, your system will be ready for rebooting. To boot your system into the upgrade process, type the following command in a terminal:

  # dnf system-upgrade reboot

More details in Fedora Magazine.