\section{Changes in Version -10}

Since version -09, the following changes have been made. 

\begin{itemize}
\item \header{Content-Encoding} changed to ``optional'' in
Table~\ref{tab:headers1}.

\item URL element \header{hname} element now set to \header{1*uric}
instead of \header{*uric}.

\item \header{Call-ID} \header{local-id} element now set to
\header{1*uric} instead of \header{*uric}.

\item Reference to DNS MX records removed.

\item \header{signed-by} value enclosed in quotation marks to avoid
ambiguity for semicolon.

\item \header{Allow} and \header{Content-Encoding} syntax definitions
added, to avoid possible confusion about the meaning of the
\header{Method} item and to allow inclusion of the abbreviation,
respectively.

\item Clarified the rule for adding \header{tag}s to \header{To} headers
in responses to simply count \header{Via} headers. This seems easier to
implement than having a client decide whether there are other clients
with the same URI out there.

\item Explicitly state that {\REGISTER} requests are ordered according
to arrival.  Anything else (\header{CSeq} within \header{Call-ID},
\header{Date}) does not work for any reasonable amount of server
complexity.

\item Suggest use of standard display name ``Anonymous'' for anonymous
calls, to simplify blocking and in the spirit of similar conventions for
caller-ID. (Clearly, this is only meaningful for requests signed by a
third party.)

\item Clarified \header{Via} header processing.

\item Replaced reference to URI draft with RFC 2396.

\item Removed references to UUID draft and simply required tags and
local call id values to be cryptographically random.  (Necessary since
the UUID draft is not yet an RFC.)

\item Emphasized that a proxies that accept TCP connections cannot be
stateless. If they were, they could loose the UDP request, which would
never be retransmitted by the TCP client.

\item \header{Accept}, \header{Accept-Language} and
\header{Accept-Encoding} can also appear in 415 responses if the message
body of the request was not understood.

\end{itemize}
