[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(appWillResignActive)
                                             name:UIApplicationWillResignActiveNotification
                                           object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(appWillTerminate)
                                             name:UIApplicationWillTerminateNotification
                                           object:nil];

-(void)appWillResignActive
{
    // Sample dictionary
    NSDictionary *dicState = @{ @"userName" : senderName, // Optional
                                @"status"   : @"Away", // Or whatever
                                @"isTyping" : @FALSE // Optional
                              };

    [AppDel.client setState: dicState
                    forUUID: senderId // current user's UUID
                  onChannel: KPubNubChannelName // channel name
             withCompletion: ^(PNClientStateUpdateStatus *status)
     {
         NSLog(@"%@", status);
     }];
}

- (void)client:(PubNub *)client didReceivePresenceEvent:(PNPresenceEventResult *)event
{
    if (![event.data.channel isEqualToString:event.data.subscription])
    {
        // Presence event has been received on channel group stored in event.data.subscription.
    }
    else
    {
        // Presence event has been received on channel stored in event.data.channel.
    }

    if (![event.data.presenceEvent isEqualToString:@"state-change"]) {

        NSLog(@"%@ "%@'ed"nat: %@ on %@ (Occupancy: %@)", event.data.presence.uuid,
              event.data.presenceEvent, event.data.presence.timetoken, event.data.channel,
              event.data.presence.occupancy);
    }
    else {

        NSLog(@"%@ changed state at: %@ on %@ to: %@", event.data.presence.uuid,
              event.data.presence.timetoken, event.data.channel, event.data.presence.state);
    }
}