Following the instructions on https://fedoraproject.org/wiki/DNF_system_upgrade eventually I reached dnf system-upgrade download --refresh --releasever=25 which apparently completed without error, ending by directing to run dnf system-upgrade reboot. So, I did, and it booted normally. Nothing is running that isn't supposed to be running in a normal boot. dnf system-upgrade log reports no logs found. The only dnf string in journalctl -b is starting the makecache timer. This is not the first time I've tried those wiki page instructions exactly like this with same result. What's supposed to be happening that isn't?