Major Changes between Version 02 and Cersion 02 of the Proposal for an IETF Header Registry:

By Jacob Palme, e-mail:, at the research group for CMC (Computer Mediated Communication) in the Department of Computer and Systems Sciences at Stockholm University and KTH.

The new draft can be found at URL:

Changed title to include HTTP

The title has been changed to " Mail, Netnews and HTTP header field Registration Procedure" so that also HTTP headers are included.

Addition in chapter 1 of the text:

   This registry can contain header fields starting with "X-", even though
   such header fields cannot be specified in IETF standards.

Change in chapter 2 "Headers implemented in new products" added:

   The header field name registry can contain header fields from the
   following sources:
   - Internet standards
   - RFCs which are not Internet standards
   - Non-Internet standards
   - Other commonly used headers fields
   - Headers implemented in new products
   - Sometimes used header fields whose use is discouraged.

Change in chapter 2; HTTP headings added:

   The registry can contain header fields used in e-mail message headings,
   MIME content headings, HTTP headings and Usenet News article headings.

Change in chapter 4, the registration template is now specified as:

     4.1 Registration Template
     Subject: Registration of header field: XXX
     Header field name:
     Header field status (choices, see section 
     5.2 Header field Status below)
     What is the header field used for:
     Who can set or modify the header field:
     Protocols which use this header field:
     (One or more of E-MAIL MESSAGE HEADING,
     Application programs which use this header field:
     Encoding considerations:
     Security considerations:
     Interoperability considerations:
     Published specification:
     Person & email address to contact for further information:
     Author/Change controller:
     (Any other information that the author deems interesting may
     be added below this line.)

The format of the published header registry is now specified in the following way in chapter 4.3:

    (1) In plain formatted ASCII text as shown in section 11.1.
    (2) In HTML format as shown in section 11.2.
    (3) As ASCII text with HT between fields and CRLF between lines
        as shown in section 11.3.

Two new added sections:

   4.4 Changes to registered headers
   Minor changes to registered headers, which will not cause problems
   for those who have already implemented the header, can be done by
   the person or organisation who has change control for the header.
   This person or organisation can also add to the register advance
   notice about future changes under development.
   Changes made by an revised version of an IETF standard should be
   made at the same time as the publication of the revised standard.
   Other changes require the same approval procedure as for registration
   of new headers.
   4.5 Registration of headers from Internet drafts
   Headers in Internet drafts can be registered on a temporary basis,
   so that the header registry can be used to find also such headers.
   If the IETF draft expires, such headers must either be removed
   from the registry, or changed to reflect their new status (as an
   IETF standard or as a non-standard documented separately from IETF).

Changed examples in the appendix

The appendix has been modified to show examples of the three new publication formats. These examples can also be found at URL