diff --git a/WORKSPACE b/WORKSPACE
index 37dfd50ce..a2798b7f0 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -26,7 +26,7 @@
 #
 # A Bazel (http://bazel.io) workspace for the Google Cloud Endpoints runtime.
 
-ISTIO_PROXY = "76355366e4adc6d4002d69d5aafa57e1606338ee"
+ISTIO_PROXY = "6e372fc510de08da504c2dd21060c09255c1aee7"
 
 git_repository(
     name = "nginx",
diff --git a/src/grpc/proxy_flow.cc b/src/grpc/proxy_flow.cc
index 009f37491..811a13cb9 100644
--- a/src/grpc/proxy_flow.cc
+++ b/src/grpc/proxy_flow.cc
@@ -31,6 +31,7 @@
 #include "grpc/support/alloc.h"
 
 extern "C" {
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/security/util/b64.h"
 }
 
@@ -130,6 +131,8 @@ namespace {
 Status ProcessDownstreamHeaders(
     const std::multimap<std::string, std::string> &headers,
     ::grpc::ClientContext *context) {
+  static grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+
   for (const auto &it : headers) {
     // GRPC runtime libraries use "-bin" suffix to detect binary headers and
     // properly apply base64 encoding & decoding as headers are sent and
@@ -140,8 +143,8 @@ Status ProcessDownstreamHeaders(
         continue;
       }
       ::grpc::Slice value_slice(
-          grpc_base64_decode_with_len(it.second.c_str(), it.second.length(),
-                                      false),
+          grpc_base64_decode_with_len(&exec_ctx, it.second.c_str(),
+                                      it.second.length(), false),
           ::grpc::Slice::STEAL_REF);
       std::string binary_value(
           reinterpret_cast<const char *>(value_slice.begin()),
diff --git a/src/nginx/t/grpc_api_key.t b/src/nginx/t/grpc_api_key.t
index 7c25cfe7f..7a2a31c82 100644
--- a/src/nginx/t/grpc_api_key.t
+++ b/src/nginx/t/grpc_api_key.t
@@ -135,8 +135,8 @@ my $expected_report_body = ServiceControl::gen_report_body({
   'http_method' => 'POST',
   'log_message' => 'Method: test.grpc.Test.Echo',
   'response_code' => '200',
-  'request_size' => ($^O eq 'darwin' ? 313 : 315),
-  'request_bytes' => ($^O eq 'darwin' ? 313 : 315),
+  'request_size' => ($^O eq 'darwin' ? 305 : 307),
+  'request_bytes' => ($^O eq 'darwin' ? 305 : 307),
   'streaming_request_message_counts' => 1,
   'streaming_response_message_counts' => 1,
   });
diff --git a/src/nginx/t/grpc_interop_metadata.t b/src/nginx/t/grpc_interop_metadata.t
index 8d8b57114..88c4f2731 100644
--- a/src/nginx/t/grpc_interop_metadata.t
+++ b/src/nginx/t/grpc_interop_metadata.t
@@ -89,6 +89,7 @@ my @test_cases = (
 );
 
 foreach my $case (@test_cases) {
+  <>;
   my $result = &ApiManager::run_grpc_interop_test($t, $Http2NginxPort,
       $case, '--api_key', 'api-key');
   is($result, 0, "${case} test completed as expected.");
diff --git a/src/nginx/t/grpc_streaming.t b/src/nginx/t/grpc_streaming.t
index 77336b09f..fcf3c0004 100644
--- a/src/nginx/t/grpc_streaming.t
+++ b/src/nginx/t/grpc_streaming.t
@@ -138,8 +138,8 @@ my $expected_report_body = ServiceControl::gen_report_body({
   'http_method' => 'POST',
   'log_message' => 'Method: test.grpc.Test.EchoStream',
   'response_code' => '200',
-  'request_size' => ($^O eq 'darwin' ? 499 : 501),
-  'request_bytes' => ($^O eq 'darwin' ? 499 : 501),
+  'request_size' => ($^O eq 'darwin' ? 491 : 493),
+  'request_bytes' => ($^O eq 'darwin' ? 491 : 493),
   'streaming_request_message_counts' => 10,
   'streaming_response_message_counts' => 10,
   });
diff --git a/test/grpc/BUILD b/test/grpc/BUILD
index b477fab32..64556bc49 100644
--- a/test/grpc/BUILD
+++ b/test/grpc/BUILD
@@ -93,6 +93,7 @@ cc_library(
     deps = [
         ":grpc-test_proto",
         "//external:api_manager_utils",
+        "//external:grpc++",
     ],
 )
 
@@ -121,7 +122,10 @@ cc_binary(
     name = "grpc-test-server",
     testonly = 1,
     srcs = ["grpc-test-server.cc"],
-    deps = [":grpc-test_proto"],
+    deps = [
+        ":grpc-test_proto",
+        "//external:grpc++",
+    ],
 )
 
 load(
diff --git a/test/transcoding/BUILD b/test/transcoding/BUILD
index a24998fe0..dfc50e2d1 100644
--- a/test/transcoding/BUILD
+++ b/test/transcoding/BUILD
@@ -45,7 +45,10 @@ cc_binary(
     name = "bookstore-server",
     testonly = 1,
     srcs = ["bookstore-server.cc"],
-    deps = [":bookstore"],
+    deps = [
+        ":bookstore",
+        "//external:grpc++",
+    ],
 )
 
 cc_binary(
@@ -57,6 +60,7 @@ cc_binary(
         ":bookstore",
         "//external:protobuf",
         "//external:gflags",
+        "//external:grpc++",
     ],
 )