Setver is used to imitate the version of DOS being ran in case an application 
was unable to be ran because of a newer version of MS-DOS.

For setver to work setver.exe device must be loaded in the config.sys:

Device=C:\DOS\setver.exe (For earler versions of MS-DOS)
or
Device=C:\Windows\Command\setver.exe (From Windows 95 onwards)

It sets the MS-DOS version number that Windows reports to a program.

Command Examples:

Display current version table: SETVER [drive:path] 
Add entry: SETVER [drive:path] filename n.nn
Delete entry: SETVER [drive:path] filename /DELETE [/QUIET]

[drive:path] Specifies location of the SETVER.EXE file.
filename Specifies the filename of the program.
n.nn Specifies the MS-DOS version to be reported to the program.
/DELETE or /D Deletes the version-table entry for the specified program.
/QUIET or /Q Hides the message typically displayed during deletion of
version-table entry.

EXAMPLES

setver 6.22 - This would trick programs into thinking your running 6.22