diff --git a/release/install-release.sh b/release/install-release.sh
index 334505d0..2bf8eaf2 100755
--- a/release/install-release.sh
+++ b/release/install-release.sh
@@ -161,21 +161,24 @@ extract(){
 }
 
 
-# 1: new V2Ray. 0: no
+# 1: new V2Ray. 0: no. 2: not installed. 3: check failed. 4: don't check.
 getVersion(){
     if [[ -n "$VERSION" ]]; then
         NEW_VER="$VERSION"
-        return 1
+        return 4
     else
-        CUR_VER=`/usr/bin/v2ray/v2ray -version 2>/dev/null | head -n 1 | cut -d " " -f2`
+        VER=`/usr/bin/v2ray/v2ray -version 2>/dev/null`
+        RETVAL="$?"
+        CUR_VER=`echo $VER | head -n 1 | cut -d " " -f2`
         TAG_URL="https://api.github.com/repos/v2ray/v2ray-core/releases/latest"
         NEW_VER=`curl ${PROXY} -s ${TAG_URL} --connect-timeout 10| grep 'tag_name' | cut -d\" -f4`
-
         if [[ $? -ne 0 ]] || [[ $NEW_VER == "" ]]; then
             colorEcho ${RED} "Network error! Please check your network or try again."
-            exit
+            return 3
+        elif [[ $RETVAL -ne 0 ]];then
+            return 2
         elif [[ "$NEW_VER" != "$CUR_VER" ]];then
-                return 1
+            return 1
         fi
         return 0
     fi
@@ -288,7 +291,7 @@ Help(){
     echo "  -h, --help            Show help"
     echo "  -p, --proxy           To download through a proxy server, use -p socks5://127.0.0.1:1080 or -p http://127.0.0.1:3128 etc"
     echo "  -f, --force           Force install"
-    echo "      --version         Install a particular version"
+    echo "      --version         Install a particular version, use --version v3.15"
     echo "  -l, --local           Install from a local file"
     echo "      --remove          Remove installed V2Ray"
     echo "  -c, --check           Check for update"
@@ -346,22 +349,26 @@ remove(){
 }
 
 checkUpdate(){
-        echo "Checking for update."
-        getVersion
-        if [[ $? -eq 1 ]]; then
-            colorEcho ${GREEN} "Found new version ${NEW_VER} for V2Ray."
-            exit 
-        else 
-            colorEcho ${GREEN} "No new version."
-            exit
-        fi
+    echo "Checking for update."
+    VERSION=""
+    getVersion
+    RETVAL="$?"
+    if [[ $RETVAL -eq 1 ]]; then
+        colorEcho ${GREEN} "Found new version ${NEW_VER} for V2Ray.(Current version:$CUR_VER)"
+    elif [[ $RETVAL -eq 0 ]]; then
+        colorEcho ${GREEN} "No new version. Current version is ${NEW_VER}."
+    elif [[ $RETVAL -eq 2 ]]; then
+        colorEcho ${RED} "No V2Ray installed."
+        colorEcho ${GREEN} "The newest version for V2Ray is ${NEW_VER}."
+    fi
+    return 0
 }
 
 main(){
     #helping information
     [[ "$HELP" == "1" ]] && Help
-    [[ "$CHECK" == "1" ]] && checkUpdate
     [[ "$REMOVE" == "1" ]] && remove
+    [[ "$CHECK" == "1" ]] && checkUpdate && return
     
     sysArch
     # extract local file
@@ -385,9 +392,14 @@ main(){
         # download via network and extract
         installSoftware "curl"
         getVersion
-        if [[ $? == 0 ]] && [[ "$FORCE" != "1" ]]; then
+        RETVAL="$?"
+        if [[ $RETVAL == 0 ]] && [[ "$FORCE" != "1" ]]; then
             colorEcho ${GREEN} "Latest version ${NEW_VER} is already installed."
-            exit
+            return
+        elif [[ $RETVAL == 3 ]]; then
+            return 3
+        elif [[ $RETVAL == 1 ]]; then
+            colorEcho ${GREEN} "Found new version ${NEW_VER} for V2Ray.(Current version:$CUR_VER)"
         else
             colorEcho ${BLUE} "Installing V2Ray ${NEW_VER} on ${ARCH}"
             downloadV2Ray