VERSION version-number software-identifier
This command requests or specifies the protocol version number. If the specified protocol version number is not supported, the response will be:
VERSION-NOT-SUPPORTED TRY min-version-number-max-version-number
or
VERSION-NOT-SUPPORTED TRY version-number
Where version-number or min-version-number-max-version-number are those versions that are supported. If no arguments are supplied (or if the argument is not a number), then the VERSION command will return the current protocol version number being used by the server in the form:
VERSION version-number software-identifier
If the software-identifier is specified, it identifies
the software and version of the software that is generating the
message.