Upgrade Fedora 40 oneliner
dnf -y up --ref && \
dnf -y in dnf-plugin-system-upgrade && \
dnf -y system-upgrade download --releasever=39 && \
dnf system-upgrade reboot
dnf -y up --ref && \
dnf -y in dnf-plugin-system-upgrade && \
dnf -y system-upgrade download --releasever=39 && \
dnf system-upgrade reboot