So I have a MacBook Air, with Parallels Desktop 7 installed. I am running Windows XP on it. I have just bought a new MacBook Pro, and transferred everything over. I've bought a copy of Windows 8. I want to only pay an 'upgrade' price for changing to a later version of what I already have, but apparently I can't upgrade from PD 7 to 10, which is the current version, without paying the full price. If I had PD 9 however, I apparently can upgrade free to PD 10. But I cannot find anywhere how to upgrade from PD 7 to PD 9. Every link I click on on this website or an internet search, which is showing as a link to PD 9, just takes me to a PD 10 page. Can anyone tell me where I can purchase, at the 'upgrade' price, a version of PD 9?