Example:
Your customer's organization needs a new system running on the same platform as its existing systemsWindows 7 Professional.
Downgrade rights offer a practical solution. The customer can:
Purchase a PC with Windows 8 Pro preinstalled.
Downgradeat no additional costto Windows 7 Professional.
Move to Windows 8 Pro at the appropriate time. The system is licensed and ready for conversion.

OEM versions of Windows 8 eligible for downgrade
Windows 8 Pro includes downgrade rights to:

Windows 7 Professional
Windows Vista Business