The ProtocolVersion property sets or returns the current
HTTP version number. It is used to determine how requests are
submitted to the server, as well as what header fields are required.
The default value for this property is "1.0", and should be
changed before any connection attempt is made by the client.
Note that setting the property value to "0.9" tells the
control to use the preliminary protocol specification which only
supported a basic version of the GET command, and did not have any
provisions for features such as user authentication, virtual hosting,
etc. Header fields are not supported in this version of the