diff --git a/client/client.go b/client/client.go
index e933c8b..3f281fd 100644
--- a/client/client.go
+++ b/client/client.go
@@ -315,7 +315,7 @@ func (c *client) rpcWriter(stopChan <-chan struct{}, writerDone chan<- error) {
 			}
 
 			err = fmt.Errorf("Client: Cannot send request to wire: [%s]", err)
-			logging.Logger().Error(err.Error())
+			logging.Logger().Error(err)
 			continue
 		}
 	}
@@ -343,8 +343,7 @@ func (c *client) rpcReader(readerDone chan<- error) {
 				logging.Logger().Infof("Client: disconnected from server")
 				return
 			}
-			err = fmt.Errorf("Client: Cannot decode response or notify: [%s]", err)
-			logging.Logger().Error(err.Error())
+			logging.Logger().Errorf("Client: Cannot decode response or notify: [%s]", err)
 			continue
 		}
 
diff --git a/protocol/json/client_notification.go b/protocol/json/client_notification.go
index d65a9a1..0c96da2 100644
--- a/protocol/json/client_notification.go
+++ b/protocol/json/client_notification.go
@@ -26,6 +26,10 @@ type ClientNotificationCodec struct {
 	codec codec.Codec
 }
 
+func (cnc *ClientNotificationCodec) HasResponse() bool {
+	return false
+}
+
 func (cnc *ClientNotificationCodec) Method() string {
 	return cnc.noti.Method
 }
diff --git a/protocol/registry_codec.go b/protocol/registry_codec.go
index b0ecc68..88adc7e 100644
--- a/protocol/registry_codec.go
+++ b/protocol/registry_codec.go
@@ -10,4 +10,6 @@ type RegistryCodec interface {
 	// Reads the request filling the RPC method args.
 	ReadParams(args []interface{}) error
 	Params() ([]string, error)
+
+	HasResponse() bool
 }
diff --git a/protocol/server_codec.go b/protocol/server_codec.go
index 219af30..92f98de 100644
--- a/protocol/server_codec.go
+++ b/protocol/server_codec.go
@@ -15,7 +15,6 @@ type ServerCodec interface {
 type ServerRequestCodec interface {
 	RegistryCodec
 
-	HasResponse() bool
 	WriteResponse(w io.Writer, reply interface{}) error
 	WriteError(w io.Writer, status int, err error) error
 }