The short answer is a little bit of "yes", and a whole lotta "no", at least in the way that most people expect upgrades to work.
Here's how I found out...
By mistake I ordered copies of the Windows 8 upgrade edition. All that really means is that rather than being able to install Windows 8 to a clean or "bare metal" machine, there needs to be a prior version of Windows 7, Windows Vista or Windows XP installed.
The option of Windows XP confused me, because Windows 7 didn't really handle that scenario well - effectively there was no upgrade from XP to Windows 7, and yet it appeared that that might have changed with Windows 8.
As it turns out things may be a little more streamlined perhaps, but that's about it.
I'll walk you through my upgrade and point out the relevant points when upgrading from Windows XP.