2.2.1.3.2 Server
The Server Response header field specifies the software that handled the request and originated the response.
Server = "Server:" server-product-name "/" version CRLF; (see [RFC1945], section 10.14)
server-product-name = 1*CHAR
The version uses the <Major Version>.<Minor Version> numbering scheme.
Version = 1*DIGIT "." 1*DIGIT
The server sets the token value to a string identifying the server product. The implementers SHOULD set the token value to a string identifying their product and product version.<4>