* GroupDAV object URL's are now based on the EUID of a message (which is

* GroupDAV object URL's are now based on the EUID of a message (which is
  derived from the UID of the groupware object itself) instead of the
  message number.  This was done in order to conform to GroupDAV's
  requirement that the URL cannot change after an object is updated.
* The ETag of a GroupDAV object is still the message number, and in fact
  doing so meets that requirement perfectly.