fix coap efento callbacks

common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/callback/CoapEfentoCallback.java

@@ -34,10 +34,9 @@ public class CoapEfentoCallback implements TransportServiceCallback<Void> {
 
     @Override
     public void onSuccess(Void msg) {
+        //We respond only to confirmed requests in order to reduce battery consumption for Efento devices.
         if (isConRequest()) {
-            Response response = new Response(onSuccessResponse);
+            exchange.respond(new Response(onSuccessResponse));
-            response.setAcknowledged(true);
-            exchange.respond(response);
         }
     }
 

common/transport/coap/src/main/java/org/thingsboard/server/transport/coap/efento/CoapEfentoTransportResource.java

@@ -99,10 +99,9 @@ public class CoapEfentoTransportResource extends AbstractCoapTransportResource {
                 break;
             case DEVICE_INFO:
             case CONFIGURATION:
-                Response response = new Response(CoAP.ResponseCode.CREATED);
+                //We respond only to confirmed requests in order to reduce battery consumption for Efento devices.
                 if (exchange.advanced().getRequest().isConfirmable()) {
-                    response.setAcknowledged(true);
+                    exchange.respond(new Response(CoAP.ResponseCode.CREATED));
-                    exchange.respond(response);
                 }
                 break;
             default: