The -06 drafts contain quite a substantive changes, plus major rewrites in 
Parts 1 (URIs, Connections, and Message Parsing) and 6 (Caching). All
non-editorial changes should be mentioned in the "Changes Since ..." 
appendices; diffs are available from tools.ietf.org (linked from the HTMLized
versions) and from
<http://svn.tools.ietf.org/svn/wg/httpbis/draft-ietf-httpbis/diffs/>.

The top changes are:

- Many parts of Part 6 (Caching) have been rewritten from scratch, resulting 
  in a more compact spec. There are several open issues and TODOS related
  to this change, so please pay attention to the inlined comments.
  
- All the issues around the BNF format and implied LWS have been resolved, see
  <http://tools.ietf.org/wg/httpbis/trac/ticket/36> for details.
  
- In Part 1, the HTTP URL definition has been updated to be based on RFC 3986,
  quite some text in the introductory chapters has been updated, and lots
  of historic stuff (better summarized in RFC 3986) has been removed.
  
We think the issue below have been resolved with these drafts, and are 
planning to close them soonish:

- #30: "Header LWS" (<http://tools.ietf.org/wg/httpbis/trac/ticket/30>)
- #63: "RFC2047 encoded words" (<http://tools.ietf.org/wg/httpbis/trac/ticket/63>)
- #74: "Character Encodings in TEXT" (<http://tools.ietf.org/wg/httpbis/trac/ticket/74>)
- #77: "Line folding" (<http://tools.ietf.org/wg/httpbis/trac/ticket/77>)
- #83: "OPTIONS * and proxies" (<http://tools.ietf.org/wg/httpbis/trac/ticket/83>)
- #85: "Custom Ranges" (<http://tools.ietf.org/wg/httpbis/trac/ticket/85>)
- #111: "Use of TEXT" (<http://tools.ietf.org/wg/httpbis/trac/ticket/111>)