diff --git a/.kokoro/populate-secrets.sh b/.kokoro/populate-secrets.sh
new file mode 100755
index 0000000..85801f4
--- /dev/null
+++ b/.kokoro/populate-secrets.sh
@@ -0,0 +1,32 @@
+#!/bin/bash
+# Copyright 2020 Google LLC.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -eo pipefail
+
+# Populates requested secrets set in SECRET_MANAGER_KEYS from service account:
+# kokoro-trampoline@cloud-devrel-kokoro-resources.iam.gserviceaccount.com
+SECRET_LOCATION="${KOKORO_GFILE_DIR}/secret_manager"
+mkdir -p ${SECRET_LOCATION}
+for key in $(echo ${SECRET_MANAGER_KEYS} | sed "s/,/ /g")
+do
+  docker run --entrypoint=gcloud \
+    --volume=${KOKORO_GFILE_DIR}:${KOKORO_GFILE_DIR} \
+    gcr.io/google.com/cloudsdktool/cloud-sdk \
+    secrets versions access latest \
+    --credential-file-override=${KOKORO_GFILE_DIR}/kokoro-trampoline.service-account.json \
+    --project cloud-devrel-kokoro-resources \
+    --secret $key > \
+    "$SECRET_LOCATION/$key"
+done
diff --git a/.kokoro/publish.sh b/.kokoro/publish.sh
index 3399c5b..24957d7 100755
--- a/.kokoro/publish.sh
+++ b/.kokoro/publish.sh
@@ -24,7 +24,7 @@ python3 -m releasetool publish-reporter-script > /tmp/publisher-script; source /
 
 cd $(dirname $0)/..
 
-NPM_TOKEN=$(cat $KOKORO_KEYSTORE_DIR/73713_google-cloud-cloudbuild-npm-token)
+NPM_TOKEN=$(cat $KOKORO_GFILE_DIR/secret_manager/npm_publish_token
 echo "//wombat-dressing-room.appspot.com/:_authToken=${NPM_TOKEN}" > ~/.npmrc
 
 npm install
diff --git a/.kokoro/release/publish.cfg b/.kokoro/release/publish.cfg
index de1ed79..10ffe1b 100644
--- a/.kokoro/release/publish.cfg
+++ b/.kokoro/release/publish.cfg
@@ -47,13 +47,9 @@ before_action {
   }
 }
 
-before_action {
-  fetch_keystore {
-    keystore_resource {
-      keystore_config_id: 73713
-      keyname: "google-cloud-cloudbuild-npm-token"
-    }
-  }
+env_vars: {
+  key: "SECRET_MANAGER_KEYS"
+  value: "npm_publish_token"
 }
 
 # Download trampoline resources.
diff --git a/.kokoro/trampoline.sh b/.kokoro/trampoline.sh
index 9bd4905..a4241db 100755
--- a/.kokoro/trampoline.sh
+++ b/.kokoro/trampoline.sh
@@ -24,4 +24,5 @@ function cleanup() {
 }
 trap cleanup EXIT
 
+$(dirname $0)/populate-secrets.sh # Secret Manager secrets.
 python3 "${KOKORO_GFILE_DIR}/trampoline_v1.py"
diff --git a/protos/protos.d.ts b/protos/protos.d.ts
index 7e72a79..100f8b7 100644
--- a/protos/protos.d.ts
+++ b/protos/protos.d.ts
@@ -6281,6 +6281,9 @@ export namespace google {
 
             /** FieldDescriptorProto options */
             options?: (google.protobuf.IFieldOptions|null);
+
+            /** FieldDescriptorProto proto3Optional */
+            proto3Optional?: (boolean|null);
         }
 
         /** Represents a FieldDescriptorProto. */
@@ -6322,6 +6325,9 @@ export namespace google {
             /** FieldDescriptorProto options. */
             public options?: (google.protobuf.IFieldOptions|null);
 
+            /** FieldDescriptorProto proto3Optional. */
+            public proto3Optional: boolean;
+
             /**
              * Creates a new FieldDescriptorProto instance using the specified properties.
              * @param [properties] Properties to set
diff --git a/protos/protos.js b/protos/protos.js
index d28ce8d..2eb62e4 100644
--- a/protos/protos.js
+++ b/protos/protos.js
@@ -28,7 +28,7 @@
     var $Reader = $protobuf.Reader, $Writer = $protobuf.Writer, $util = $protobuf.util;
     
     // Exported root namespace
-    var $root = $protobuf.roots._google_cloud_cloudbuild_1_5_0_protos || ($protobuf.roots._google_cloud_cloudbuild_1_5_0_protos = {});
+    var $root = $protobuf.roots._google_cloud_cloudbuild_protos || ($protobuf.roots._google_cloud_cloudbuild_protos = {});
     
     $root.google = (function() {
     
@@ -16189,6 +16189,7 @@
                  * @property {number|null} [oneofIndex] FieldDescriptorProto oneofIndex
                  * @property {string|null} [jsonName] FieldDescriptorProto jsonName
                  * @property {google.protobuf.IFieldOptions|null} [options] FieldDescriptorProto options
+                 * @property {boolean|null} [proto3Optional] FieldDescriptorProto proto3Optional
                  */
     
                 /**
@@ -16286,6 +16287,14 @@
                  */
                 FieldDescriptorProto.prototype.options = null;
     
+                /**
+                 * FieldDescriptorProto proto3Optional.
+                 * @member {boolean} proto3Optional
+                 * @memberof google.protobuf.FieldDescriptorProto
+                 * @instance
+                 */
+                FieldDescriptorProto.prototype.proto3Optional = false;
+    
                 /**
                  * Creates a new FieldDescriptorProto instance using the specified properties.
                  * @function create
@@ -16330,6 +16339,8 @@
                         writer.uint32(/* id 9, wireType 0 =*/72).int32(message.oneofIndex);
                     if (message.jsonName != null && Object.hasOwnProperty.call(message, "jsonName"))
                         writer.uint32(/* id 10, wireType 2 =*/82).string(message.jsonName);
+                    if (message.proto3Optional != null && Object.hasOwnProperty.call(message, "proto3Optional"))
+                        writer.uint32(/* id 17, wireType 0 =*/136).bool(message.proto3Optional);
                     return writer;
                 };
     
@@ -16394,6 +16405,9 @@
                         case 8:
                             message.options = $root.google.protobuf.FieldOptions.decode(reader, reader.uint32());
                             break;
+                        case 17:
+                            message.proto3Optional = reader.bool();
+                            break;
                         default:
                             reader.skipType(tag & 7);
                             break;
@@ -16488,6 +16502,9 @@
                         if (error)
                             return "options." + error;
                     }
+                    if (message.proto3Optional != null && message.hasOwnProperty("proto3Optional"))
+                        if (typeof message.proto3Optional !== "boolean")
+                            return "proto3Optional: boolean expected";
                     return null;
                 };
     
@@ -16610,6 +16627,8 @@
                             throw TypeError(".google.protobuf.FieldDescriptorProto.options: object expected");
                         message.options = $root.google.protobuf.FieldOptions.fromObject(object.options);
                     }
+                    if (object.proto3Optional != null)
+                        message.proto3Optional = Boolean(object.proto3Optional);
                     return message;
                 };
     
@@ -16637,6 +16656,7 @@
                         object.options = null;
                         object.oneofIndex = 0;
                         object.jsonName = "";
+                        object.proto3Optional = false;
                     }
                     if (message.name != null && message.hasOwnProperty("name"))
                         object.name = message.name;
@@ -16658,6 +16678,8 @@
                         object.oneofIndex = message.oneofIndex;
                     if (message.jsonName != null && message.hasOwnProperty("jsonName"))
                         object.jsonName = message.jsonName;
+                    if (message.proto3Optional != null && message.hasOwnProperty("proto3Optional"))
+                        object.proto3Optional = message.proto3Optional;
                     return object;
                 };
     
@@ -18449,7 +18471,7 @@
                  * @memberof google.protobuf.FileOptions
                  * @instance
                  */
-                FileOptions.prototype.ccEnableArenas = false;
+                FileOptions.prototype.ccEnableArenas = true;
     
                 /**
                  * FileOptions objcClassPrefix.
@@ -18898,7 +18920,7 @@
                         object.javaGenerateEqualsAndHash = false;
                         object.deprecated = false;
                         object.javaStringCheckUtf8 = false;
-                        object.ccEnableArenas = false;
+                        object.ccEnableArenas = true;
                         object.objcClassPrefix = "";
                         object.csharpNamespace = "";
                         object.swiftPrefix = "";
diff --git a/protos/protos.json b/protos/protos.json
index 3c7648f..c5013b0 100644
--- a/protos/protos.json
+++ b/protos/protos.json
@@ -1632,6 +1632,10 @@
                 "options": {
                   "type": "FieldOptions",
                   "id": 8
+                },
+                "proto3Optional": {
+                  "type": "bool",
+                  "id": 17
                 }
               },
               "nested": {
@@ -1867,7 +1871,7 @@
                   "type": "bool",
                   "id": 31,
                   "options": {
-                    "default": false
+                    "default": true
                   }
                 },
                 "objcClassPrefix": {
diff --git a/src/v1/cloud_build_client.ts b/src/v1/cloud_build_client.ts
index e4be729..e945567 100644
--- a/src/v1/cloud_build_client.ts
+++ b/src/v1/cloud_build_client.ts
@@ -107,6 +107,13 @@ export class CloudBuildClient {
     }
     opts.servicePath = opts.servicePath || servicePath;
     opts.port = opts.port || port;
+
+    // users can override the config from client side, like retry codes name.
+    // The detailed structure of the clientConfig can be found here: https://github.com/googleapis/gax-nodejs/blob/master/src/gax.ts#L546
+    // The way to override client config for Showcase API:
+    //
+    // const customConfig = {"interfaces": {"google.showcase.v1beta1.Echo": {"methods": {"Echo": {"retry_codes_name": "idempotent", "retry_params_name": "default"}}}}}
+    // const showcaseClient = new showcaseClient({ projectId, customConfig });
     opts.clientConfig = opts.clientConfig || {};
 
     const isBrowser = typeof window !== 'undefined';
diff --git a/synth.metadata b/synth.metadata
index 6eeab3a..4105e4e 100644
--- a/synth.metadata
+++ b/synth.metadata
@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/nodejs-cloudbuild.git",
-        "sha": "aa7d99b9c02267808cac07f7691f5ce62f06ca14"
+        "sha": "2bed454946812b16a995422f773b2406a69d1d2d"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "be74d3e532faa47eb59f1a0eaebde0860d1d8ab4"
+        "sha": "1c92077459db3dc50741e878f98b08c6261181e0"
       }
     }
   ],
diff --git a/tsconfig.json b/tsconfig.json
index 613d355..c78f1c8 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -5,7 +5,7 @@
     "outDir": "build",
     "resolveJsonModule": true,
     "lib": [
-      "es2016",
+      "es2018",
       "dom"
     ]
   },