What do you mean "it doesn't work"?
If there's no upgrade key then upgrade will proceed without it. If there is one then you'll get asked for it. I'm not sure what the other possibilities are.
And just for completeness, what version of Moodle are you running / upgrading to?
If there's no upgrade key then upgrade will proceed without it. If there is one then you'll get asked for it. I'm not sure what the other possibilities are.
And just for completeness, what version of Moodle are you running / upgrading to?