By default this manager is disabled. If you support last message correction, explicitly enable it and check inbound messages for the Replace extension.

Advertising support for message correction

 xmppSession.getManager(MessageCorrectionManager.class).setEnabled(true);
 

Checking if a message should be corrected

 Replace replace = message.getExtension(Replace.class);
 if (replace != null) {
     String oldMessageId = replace.getId();
     // Replace old message with message...
 }