The service is responsible for removing all the occupants. It SHOULD NOT broadcast presence stanzas of type "unavailable" from all occupants, instead sending only one presence stanza of type "unavailable" to each occupant so that the user knows he or she has been removed from the room. If extended presence information specifying the JID of an alternate location and the reason for the room destruction was provided by the room owner, the presence stanza MUST include that information.
+The service is responsible for removing all the occupants. It SHOULD NOT broadcast presence stanzas of type "unavailable" from all occupants, instead sending only one presence stanza of type "unavailable" to each occupant so that the user knows he or she has been removed from the room. The extended presence information of the stanza MUST include <destroy/> element. If extended information specifying the JID of an alternate location and/or the reason for the room destruction was provided by the room owner, the presence stanza MUST include that information.
+Note: in older versions of this standard, the inclusion of a <destroy/> element was not explicitly defined to be mandatory (when no alternate location or reason are provided by the room owner). Implementations therefore cannot reliably depend on the existence of this element to identify a room destruction event.