Standard XMPP clients still work. If you use Pidgin or Adium or other similar clients, you can still send and receive messages to Google users regardless of whe

Standard XMPP clients still work. If you use Pidgin or Adium or other similar clients, you can still send and receive messages to Google users regardless of whether they're using Hangouts. If you have an App Engine instance, and it uses the App Engine XMPP Service[1] to send messages to people, then that will stop working for users who switch to Hangouts. [1] https://developers.google.com/appengine/articles/using_xmpp https://developers.google.com/appengine/articles/using_xmpp