# Feature Notes for Major Revisions

This page lists the major changes that happened between different major versions of D-Bus.  


## 1.0.x to 1.2.x (including 1.1.20)

* Features 
   * The system bus now supports starting services on demand. This uses a setuid helper program because system bus daemon runs as a nobody user, while services it launches may need to run as a different user. 
      * A design doc is available in doc/system-activation.txt 
   * The TCP address format has been enhanced, such that TCP may be actually usable.   
      * The dbus-daemon man page describes the new elements in the address format. 
   * Support ANONYMOUS mechanism for authentication, which allows a client to authenticate as nobody in particular 
      * The ANONYMOUS support means you can now use D-Bus (without a bus daemon) as a protocol for a network service provided to anonymous Internet or LAN clients. 
   * Autolaunched busses now save their parameters in X11 if possible making them behave closer to busses launched through the normal mechanisms  
   * inotify is now the default backend for watching configuration file changes 
   * Better thread support. 
   * The bus daemon now generates a globally-unique ID for itself.  
      * Use this as a unique ID for a user's session, for example. 
   * Support for message serialization added for use with external transports like TUBES!!! 
   * Better eavesdropping support now picks up reply messages for debugging 
* Library API additions 
   * dbus_connection_set_allow_anonymous() - allow the message stream to begin if the client auths as anonymous (otherwise, the client will be dropped unless they auth as a user). 
   * dbus_watch_get_unix_fd() - replaces dbus_watch_get_fd  
   * dbus_watch_get_socket() - replaces dbus_watch_get_fd 
   * dbus_server_get_id() - available to access the unique ID of a particular address 
   * dbus_connection_get_server_id() - available to access the unique ID of a particular address 
   * dbus_message_marshal() - serializes a message into a byte array 
   * dbus_message_demarshal() - de-serializes a byte array into a message 
* Library API deprecations 
   * dbus_watch_get_fd() - had unclear cross-platform semantics 
* Protocol additions 
   * Argument path matching of the type arg0path='/aa/bb/' is now supported 
   * New error org.freedesktop.DBus.Error.[[ObjectPathInUse|ObjectPathInUse]] added 
   * ANONYMOUS auth support added 
   * [[GetAll|GetAll]] call added to the properties interface for getting a list of properties an object exports