diff --git a/Makefile b/Makefile
index 32eeff4..d8a4a67 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,5 @@
 .PHONY: all
 
-VERSION=0.0.1
-
 DEPS := $(wildcard *.go)
 BUILD_IMAGE := "gorush-build"
 TEST_IMAGE := "gorush-testing"
diff --git a/README.md b/README.md
index e817ae9..a9abdbc 100644
--- a/README.md
+++ b/README.md
@@ -95,12 +95,13 @@ $ gorush -android -m="your message" -k="API Key" -t="Device token"
 Send single notification with the following command.
 
 ```bash
-$ gorush -ios -m="your message" -i="your certificate path" -t="device token"
+$ gorush -ios -m="your message" -i="your certificate path" -t="device token" -topic="apns topic"
 ```
 
 * `-m`: Notification message.
 * `-i`: Apple Push Notification Certificate path (`pem` file).
 * `-t`: Device token.
+* `-topic`: The topic of the remote notification.
 
 The default endpoint is APNs development. Please add `-production` flag for APNs production push endpoint.
 
diff --git a/gorush.go b/gorush.go
index 7e48168..afc28df 100644
--- a/gorush.go
+++ b/gorush.go
@@ -27,6 +27,7 @@ func main() {
 	android := flag.Bool("android", false, "send android notification")
 	ios := flag.Bool("ios", false, "send ios notification")
 	production := flag.Bool("production", false, "production mode in iOS")
+	topic := flag.String("topic", "", "apns topic in iOS")
 
 	flag.Parse()
 
@@ -104,6 +105,10 @@ func main() {
 			Message:  *message,
 		}
 
+		if *topic != "" {
+			req.Topic = *topic
+		}
+
 		err := gorush.CheckMessage(req)
 
 		if err != nil {