It did report ‘Release upgrade success.’ However, after reboot I needed a login, username ‘user’ with the old password, empty password and with ‘changeme’ did not work.
There was no hint in the instruction on what the password shall be (before in version 17, I didnt need to enter a password).
Given that this is an upgrade, you probably don’t have a sysmaint boot mode available. The upgrade process hasn’t been observed to lock people out previously, but if you had the user’s password locked and were relying on autologin to give you access, that would probably cause this.
Probably the easiest way to fix this is to boot into recovery mode:
Once in a recovery shell, run passwd -d user to delete the user password, then run reboot. You should then be able to log into account user without a password.