Upgrade from Fedora 24 to Fedora 25, then Upgrade from Fedora 25 to Fedora 26
#++++++++++++++++++++++++ Upgrade from Fedora 24 to Fedora 25
1. Update packages of Fedora 24 and reboot.
# dnf upgrade -y
# reboot
2. Install the DNF plugin
# dnf install -y dnf-plugin-system-upgrade
3. Start the update with DNF
# dnf system-upgrade -y download --refresh --releasever=25
# dnf system-upgrade reboot
#++++++++++++++++++++++++ Upgrade from Fedora 25 to Fedora 26
1. Update packages of Fedora 25 and reboot.
# dnf upgrade -y
# reboot
2. Install the DNF plugin
# dnf install -y dnf-plugin-system-upgrade
3. Start the update with DNF
# dnf system-upgrade -y download --refresh --releasever=26
# dnf system-upgrade reboot