Command: callver
  CALLVER sets the FreeCOM command interpreter version number.
  CALLVER runs one program (in a new shell, using COMSPEC) with a
  fake DOS version number, or globally (only in FreeDOS)
  modify the reported DOS version (CALLVER 0.00 reverts)
Syntax:
  CALLVER x.xx [PROGRAM [ARGUMENTS]][/?]
Options:
  PROGRAM    Name of the program you want to start.
  ARGUMENTS  Options of the program you want to start.
  /?         Shows the help.
Comments:
  x.xx is the version number; each x can be any digit from 0-9.
  This command may be used for old programs which look for a certain
  DOS version.
Examples:
  callver 6.20
  callver 6.22 format c: /q
  callver 0.00               -> displays 7.10
See also:
 (setver)
  ver
  version
  Copyright © 2003 Robert Platt, updated 2011 by W. Spiegl.
  This file is derived from the FreeDOS Spec Command HOWTO.
  See the file H2Cpying for copying conditions.