I have a friend who was running software under Windows on his Mac using Parallels 6 he bought in 2010. He has an old email with the confirmation of the purchase from Parallels and the disk image file:
ParallelsDesktop-parallels-en_US-6.0.11822.604190
The email does not include a license code or number but does say:
Congratulations on the new purchase from the Parallels Online Store.
Order number: 6959951216
Received: September 21, 2010
The following email is a summary of your order. This email serves as your proof of purchase. If you paid by credit card, this charge will appear as DRI*Parallels, Inc. on your credit card billing statement.
He wants me to upgrade this to the latest Parallels 15. How do I do this? The password provided to him in the email 10 years ago does not work on your site and you've probably changed the way this works in the last 9 years.
I have already installed software using an evaluation copy of Parallels 15 so ideally I'd prefer to use a license key rather than have to install 6.0 and then upgrade to 15 if that still works.