usefor-usefor-03 April 2005

3.2.12  User-Agent

   The User-Agent header contains information about the user agent
   (typically a newsreader) generating the article, for statistical
   purposes and tracing of standards violations to specific software
   needing correction.  It is intended that this header be suitable for
   use in Email.
   user-agent      =  "User-Agent:" SP 1*product [CFWS] CRLF

   product         =  [CFWS] token [ [CFWS] "/" product-version ]

   product-version =  [CFWS] token

   This header MAY contain multiple product-tokens identifying the agent
   and any subproducts which form a significant part of the posting
   agent, listed in order of their significance for identifying the
   application.

      NOTE: This header supersedes the role performed redundantly by
      experimental headers such as X-Newsreader, X-Mailer, X-Posting-
      Agent, X-Http-User-Agent, and other headers previously used on
      Usenet and in Email for this purpose.  Use of these experimental
      headers SHOULD be discontinued in favor of the single, standard
      User-Agent header.

      NOTE: [RFC2616] describes a similar facility for the HTTP
      protocol.  This specification differs in that "{" and "}" are
      allowed in tokens (<product> and <product-version>) and comments
      are permitted wherever whitespace is allowed.

--- ../usefor-usefor-02/User-Agent.out          November 2004
+++ ../usefor-usefor-03/User-Agent.out          April 2005
@@ -5,22 +5,24 @@
    purposes and tracing of standards violations to specific software
    needing correction.  It is intended that this header be suitable for
    use in Email.
-   user-agent      =  "User-Agent:" SP 1*product CRLF
+   user-agent      =  "User-Agent:" SP 1*product [CFWS] CRLF
 
-   product         =  [CFWS] token [CFWS] [ "/" product-version ]
+   product         =  [CFWS] token [ [CFWS] "/" product-version ]
 
-   product-version =  [CFWS] token [CFWS]
+   product-version =  [CFWS] token
 
    This header MAY contain multiple product-tokens identifying the agent
    and any subproducts which form a significant part of the posting
    agent, listed in order of their significance for identifying the
    application.
+
       NOTE: This header supersedes the role performed redundantly by
-      experimental headers such as X-Newsreader, X-Mailer,
-      X-Posting-Agent, X-Http-User-Agent, and other headers previously
-      used on Usenet and in Email for this purpose.  Use of these
-      experimental headers SHOULD be discontinued in favor of the
-      single, standard User-Agent header.
+      experimental headers such as X-Newsreader, X-Mailer, X-Posting-
+      Agent, X-Http-User-Agent, and other headers previously used on
+      Usenet and in Email for this purpose.  Use of these experimental
+      headers SHOULD be discontinued in favor of the single, standard
+      User-Agent header.
+
       NOTE: [RFC2616] describes a similar facility for the HTTP
       protocol.  This specification differs in that "{" and "}" are
       allowed in tokens (<product> and <product-version>) and comments