Upgrade Fedora from the command line on UEFI installed systems
[Note in this example we explicitly reference 38, but might be another release
We recommend upgrading one release at a time]
sudo dnf upgrade --refresh
sudo reboot
login as sudo user
sudo dnf install dnf-plugin-system-upgrade
sudo dnf system-upgrade download --releasever=38
Answer y as required
sudo dnf system-upgrade reboot
this will likely take a while .... patience is a virtue (they say)