While software upgrade licenses are universally known, many vendors offer what is often called a downgrade license.
For any company owning a license, this type of scheme lets you substitute an older version in place of the newer version that you have paid the license on. This is particularly useful in the case of operating systems or office suites where the only license available might be for a current operating system such as Windows XP. You might need to run a version of the Windows 98 SE operating system in order to continue to use some particular piece of software such as a game or educational title. Or, perhaps your organization is standardized on Microsoft Office 2000, but your volume license purchase is for Office XP. With a downgrade license you can apply your volume license to Office 2000.
Microsoft offers guidelines on downgrading applications such as SQL Server, Office, and Windows on their licensing Web site. In Microsoft's case, their downgrade policy lets you convert a volume license or a non-OEM license, but prohibits downgrading software obtained through an equipment purchase as OEM software. Links on this page will take you to a brief on downgrading, as well as a downgrading chart.
Barrie Sosinsky is president of consulting company Sosinsky and Associates (Medfield MA). He has written extensively on a variety of computer topics. His company specializes in custom software (database and Web related), training and technical documentation.