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.