how to check received message is read or unread in xmpp framework in ios

i am developing chat application using xmppframework and i am successfully completed the send and receive message , but

1) if i am chat with user A and user B send me message the how can i identify the user B send me the message. (i already maintain the messages in core data so message will be saved) 2) how can i identify the received message is read or unread

NOTE : for message saving i used

 xmppMessageArchivingStorage = [XMPPMessageArchivingCoreDataStorage sharedInstance];
 xmppMessageArchivingModule = [[XMPPMessageArchiving alloc] initWithMessageArchivingStorage:xmppMessageArchivingStorage];

thanks