diff --git a/docs/install-agent.md b/docs/install-agent.md
index 9ff2e33259176a79098d136f0f97b6a72215ee3c..5f0b03c84dc644df50cad5a62bbe59a4aae3c906 100644
--- a/docs/install-agent.md
+++ b/docs/install-agent.md
@@ -32,13 +32,15 @@ extension=skywalking.so
 ; enable skywalking
 skywalking.enable = 1
 ; Set skyWalking collector version
-skywalking.version = 5
+skywalking.version = 6
 ; Set app code e.g. MyProjectName
 skywalking.app_code = MyProjectName
 ; Set skyWalking collector grpc address
 skywalking.grpc = 127.0.0.1:11800
 ; Set log path
 skywalking.log_path = /tmp
+; Set http header version
+skywalking.header_version = 2
 ```
 
 Run `report_client` to send PHP generated log information to `SkyWalking collector`
diff --git a/skywalking.c b/skywalking.c
index ef46efa9dfc317a50ecfcead2425583689bc8362..9dc360338f80126b9e0573a04459b1e5b8226c17 100644
--- a/skywalking.c
+++ b/skywalking.c
@@ -897,7 +897,6 @@ static void module_init() {
     long millisecond = zend_atol(l_millisecond, strlen(l_millisecond));
     efree(l_millisecond);
 
-    char *uid = uuid();
     i = 0;
     do {
         application_instance = serviceInstanceRegister(SKYWALKING_G(grpc), application_id, millisecond, SKY_OS_NAME,
diff --git a/src/greeter_client.cc b/src/greeter_client.cc
index a69313394ab75ad248c80dd139d7e84e5ee28196..91533d3be82be66e1f0f4e4c3703ac5177ebc143 100644
--- a/src/greeter_client.cc
+++ b/src/greeter_client.cc
@@ -22,7 +22,6 @@
 
 #include <grpc++/grpc++.h>
 
-
 #include "grpc/register/Register.grpc.pb.h"
 #include <boost/uuid/uuid.hpp>
 #include <boost/uuid/uuid_generators.hpp>
@@ -52,7 +51,7 @@ static boost::uuids::uuid boost_uuid = boost::uuids::random_generator()();
 class GreeterClient {
 public:
     GreeterClient(std::shared_ptr<Channel> channel)
-        : stub_(Register::NewStub(channel)) {}
+            : stub_(Register::NewStub(channel)) {}
 
     int serviceRegister(const std::string &service_name) {
         Services request;
@@ -78,7 +77,6 @@ public:
         return -100000;
     }
 
-
     int serviceInstanceRegister(int applicationid, long registertime, char *osname, char *hostname, int processno,
                                 char *ipv4s) {
         ServiceInstances request;
@@ -152,5 +150,4 @@ serviceInstanceRegister(char *grpc_server, int appId, long registertime, char *o
                         int processno, char *ipv4s) {
     GreeterClient greeter(grpc::CreateChannel(grpc_server, grpc::InsecureChannelCredentials()));
     return greeter.serviceInstanceRegister(appId, registertime, osname, hostname, processno, ipv4s);
-
 }