diff --git a/.flake8 b/.flake8
index ed9316381..29227d4cf 100644
--- a/.flake8
+++ b/.flake8
@@ -26,6 +26,7 @@ exclude =
   *_pb2.py
 
   # Standard linting exemptions.
+  **/.nox/**
   __pycache__,
   .git,
   *.pyc,
diff --git a/.github/.OwlBot.lock.yaml b/.github/.OwlBot.lock.yaml
new file mode 100644
index 000000000..9bdafee72
--- /dev/null
+++ b/.github/.OwlBot.lock.yaml
@@ -0,0 +1,4 @@
+docker:
+  digest: sha256:612842ba5ccf62b4e3983fe6dc453cf66883c74bc168aa62da7acaed1e2fdc93
+  image: gcr.io/repo-automation-bots/owlbot-python:latest  
+
diff --git a/.github/.OwlBot.yaml b/.github/.OwlBot.yaml
new file mode 100644
index 000000000..de1b2c823
--- /dev/null
+++ b/.github/.OwlBot.yaml
@@ -0,0 +1,19 @@
+# Copyright 2021 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.
+
+docker:
+  image: gcr.io/repo-automation-bots/owlbot-python:latest
+
+begin-after-commit-hash: f489240cef895655cc992e01fd516c7f52ebc426
+
diff --git a/.github/header-checker-lint.yml b/.github/header-checker-lint.yml
new file mode 100644
index 000000000..fc281c05b
--- /dev/null
+++ b/.github/header-checker-lint.yml
@@ -0,0 +1,15 @@
+{"allowedCopyrightHolders": ["Google LLC"],
+ "allowedLicenses": ["Apache-2.0", "MIT", "BSD-3"],
+ "ignoreFiles": ["**/requirements.txt", "**/requirements-test.txt"],
+ "sourceFileExtensions": [
+ 	"ts", 
+ 	"js", 
+ 	"java", 
+ 	"sh", 
+ 	"Dockerfile", 
+ 	"yaml", 
+ 	"py",
+ 	"html",
+ 	"txt"
+ ]
+}
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index b9daa52f1..b4243ced7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,8 +50,10 @@ docs.metadata
 
 # Virtual environment
 env/
+
+# Test logs
 coverage.xml
-sponge_log.xml
+*sponge_log.xml
 
 # System test environment variables.
 system_tests/local_test_setup
diff --git a/.kokoro/build.sh b/.kokoro/build.sh
index 9e7febd82..9f144307d 100755
--- a/.kokoro/build.sh
+++ b/.kokoro/build.sh
@@ -15,7 +15,11 @@
 
 set -eo pipefail
 
-cd github/python-storage
+if [[ -z "${PROJECT_ROOT:-}" ]]; then
+    PROJECT_ROOT="github/python-storage"
+fi
+
+cd "${PROJECT_ROOT}"
 
 # Disable buffering, so that the logs stream through.
 export PYTHONUNBUFFERED=1
@@ -30,16 +34,26 @@ export GOOGLE_APPLICATION_CREDENTIALS=${KOKORO_GFILE_DIR}/service-account.json
 export PROJECT_ID=$(cat "${KOKORO_GFILE_DIR}/project-id.json")
 
 # Remove old nox
-python3.6 -m pip uninstall --yes --quiet nox-automation
+python3 -m pip uninstall --yes --quiet nox-automation
 
 # Install nox
-python3.6 -m pip install --upgrade --quiet nox
-python3.6 -m nox --version
+python3 -m pip install --upgrade --quiet nox
+python3 -m nox --version
+
+# If this is a continuous build, send the test log to the FlakyBot.
+# See https://github.com/googleapis/repo-automation-bots/tree/master/packages/flakybot.
+if [[ $KOKORO_BUILD_ARTIFACTS_SUBDIR = *"continuous"* ]]; then
+  cleanup() {
+    chmod +x $KOKORO_GFILE_DIR/linux_amd64/flakybot
+    $KOKORO_GFILE_DIR/linux_amd64/flakybot
+  }
+  trap cleanup EXIT HUP
+fi
 
 # If NOX_SESSION is set, it only runs the specified session,
 # otherwise run all the sessions.
 if [[ -n "${NOX_SESSION:-}" ]]; then
-    python3.6 -m nox -s "${NOX_SESSION:-}"
+    python3 -m nox -s ${NOX_SESSION:-}
 else
-    python3.6 -m nox
+    python3 -m nox
 fi
diff --git a/.kokoro/docs/common.cfg b/.kokoro/docs/common.cfg
index ea96964f1..308bf124b 100644
--- a/.kokoro/docs/common.cfg
+++ b/.kokoro/docs/common.cfg
@@ -30,7 +30,7 @@ env_vars: {
 
 env_vars: {
     key: "V2_STAGING_BUCKET"
-    value: "docs-staging-v2-staging"
+    value: "docs-staging-v2"
 }
 
 # It will upload the docker image after successful builds.
diff --git a/.kokoro/docs/docs-presubmit.cfg b/.kokoro/docs/docs-presubmit.cfg
index 111810782..a5a723164 100644
--- a/.kokoro/docs/docs-presubmit.cfg
+++ b/.kokoro/docs/docs-presubmit.cfg
@@ -15,3 +15,14 @@ env_vars: {
     key: "TRAMPOLINE_IMAGE_UPLOAD"
     value: "false"
 }
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-storage/.kokoro/build.sh"
+}
+
+# Only run this nox session.
+env_vars: {
+    key: "NOX_SESSION"
+    value: "docs docfx"
+}
diff --git a/.kokoro/samples/python3.6/common.cfg b/.kokoro/samples/python3.6/common.cfg
index 6287c9952..04e100210 100644
--- a/.kokoro/samples/python3.6/common.cfg
+++ b/.kokoro/samples/python3.6/common.cfg
@@ -13,6 +13,12 @@ env_vars: {
     value: "py-3.6"
 }
 
+# Declare build specific Cloud project.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests-py36"
+}
+
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
     value: "github/python-storage/.kokoro/test-samples.sh"
diff --git a/.kokoro/samples/python3.6/periodic-head.cfg b/.kokoro/samples/python3.6/periodic-head.cfg
new file mode 100644
index 000000000..f9cfcd33e
--- /dev/null
+++ b/.kokoro/samples/python3.6/periodic-head.cfg
@@ -0,0 +1,11 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+}
diff --git a/.kokoro/samples/python3.7/common.cfg b/.kokoro/samples/python3.7/common.cfg
index fb9bedb81..0089e9b79 100644
--- a/.kokoro/samples/python3.7/common.cfg
+++ b/.kokoro/samples/python3.7/common.cfg
@@ -13,6 +13,12 @@ env_vars: {
     value: "py-3.7"
 }
 
+# Declare build specific Cloud project.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests-py37"
+}
+
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
     value: "github/python-storage/.kokoro/test-samples.sh"
diff --git a/.kokoro/samples/python3.7/periodic-head.cfg b/.kokoro/samples/python3.7/periodic-head.cfg
new file mode 100644
index 000000000..f9cfcd33e
--- /dev/null
+++ b/.kokoro/samples/python3.7/periodic-head.cfg
@@ -0,0 +1,11 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+}
diff --git a/.kokoro/samples/python3.8/common.cfg b/.kokoro/samples/python3.8/common.cfg
index 52a03a568..2f92d6c76 100644
--- a/.kokoro/samples/python3.8/common.cfg
+++ b/.kokoro/samples/python3.8/common.cfg
@@ -13,6 +13,12 @@ env_vars: {
     value: "py-3.8"
 }
 
+# Declare build specific Cloud project.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests-py38"
+}
+
 env_vars: {
     key: "TRAMPOLINE_BUILD_FILE"
     value: "github/python-storage/.kokoro/test-samples.sh"
diff --git a/.kokoro/samples/python3.8/periodic-head.cfg b/.kokoro/samples/python3.8/periodic-head.cfg
new file mode 100644
index 000000000..f9cfcd33e
--- /dev/null
+++ b/.kokoro/samples/python3.8/periodic-head.cfg
@@ -0,0 +1,11 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+}
diff --git a/.kokoro/test-samples-against-head.sh b/.kokoro/test-samples-against-head.sh
new file mode 100755
index 000000000..aa5013db2
--- /dev/null
+++ b/.kokoro/test-samples-against-head.sh
@@ -0,0 +1,28 @@
+#!/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
+#
+#     https://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.
+
+# A customized test runner for samples.
+#
+# For periodic builds, you can specify this file for testing against head.
+
+# `-e` enables the script to automatically fail when a command fails
+# `-o pipefail` sets the exit code to the rightmost comment to exit with a non-zero
+set -eo pipefail
+# Enables `**` to include files nested inside sub-folders
+shopt -s globstar
+
+cd github/python-storage
+
+exec .kokoro/test-samples-impl.sh
diff --git a/.kokoro/test-samples-impl.sh b/.kokoro/test-samples-impl.sh
new file mode 100755
index 000000000..cf5de74c1
--- /dev/null
+++ b/.kokoro/test-samples-impl.sh
@@ -0,0 +1,102 @@
+#!/bin/bash
+# Copyright 2021 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
+#
+#     https://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.
+
+
+# `-e` enables the script to automatically fail when a command fails
+# `-o pipefail` sets the exit code to the rightmost comment to exit with a non-zero
+set -eo pipefail
+# Enables `**` to include files nested inside sub-folders
+shopt -s globstar
+
+# Exit early if samples directory doesn't exist
+if [ ! -d "./samples" ]; then
+  echo "No tests run. `./samples` not found"
+  exit 0
+fi
+
+# Disable buffering, so that the logs stream through.
+export PYTHONUNBUFFERED=1
+
+# Debug: show build environment
+env | grep KOKORO
+
+# Install nox
+python3.6 -m pip install --upgrade --quiet nox
+
+# Use secrets acessor service account to get secrets
+if [[ -f "${KOKORO_GFILE_DIR}/secrets_viewer_service_account.json" ]]; then
+    gcloud auth activate-service-account \
+	   --key-file="${KOKORO_GFILE_DIR}/secrets_viewer_service_account.json" \
+	   --project="cloud-devrel-kokoro-resources"
+fi
+
+# This script will create 3 files:
+# - testing/test-env.sh
+# - testing/service-account.json
+# - testing/client-secrets.json
+./scripts/decrypt-secrets.sh
+
+source ./testing/test-env.sh
+export GOOGLE_APPLICATION_CREDENTIALS=$(pwd)/testing/service-account.json
+
+# For cloud-run session, we activate the service account for gcloud sdk.
+gcloud auth activate-service-account \
+       --key-file "${GOOGLE_APPLICATION_CREDENTIALS}"
+
+export GOOGLE_CLIENT_SECRETS=$(pwd)/testing/client-secrets.json
+
+echo -e "\n******************** TESTING PROJECTS ********************"
+
+# Switch to 'fail at end' to allow all tests to complete before exiting.
+set +e
+# Use RTN to return a non-zero value if the test fails.
+RTN=0
+ROOT=$(pwd)
+# Find all requirements.txt in the samples directory (may break on whitespace).
+for file in samples/**/requirements.txt; do
+    cd "$ROOT"
+    # Navigate to the project folder.
+    file=$(dirname "$file")
+    cd "$file"
+
+    echo "------------------------------------------------------------"
+    echo "- testing $file"
+    echo "------------------------------------------------------------"
+
+    # Use nox to execute the tests for the project.
+    python3.6 -m nox -s "$RUN_TESTS_SESSION"
+    EXIT=$?
+
+    # If this is a periodic build, send the test log to the FlakyBot.
+    # See https://github.com/googleapis/repo-automation-bots/tree/master/packages/flakybot.
+    if [[ $KOKORO_BUILD_ARTIFACTS_SUBDIR = *"periodic"* ]]; then
+      chmod +x $KOKORO_GFILE_DIR/linux_amd64/flakybot
+      $KOKORO_GFILE_DIR/linux_amd64/flakybot
+    fi
+
+    if [[ $EXIT -ne 0 ]]; then
+      RTN=1
+      echo -e "\n Testing failed: Nox returned a non-zero exit code. \n"
+    else
+      echo -e "\n Testing completed.\n"
+    fi
+
+done
+cd "$ROOT"
+
+# Workaround for Kokoro permissions issue: delete secrets
+rm testing/{test-env.sh,client-secrets.json,service-account.json}
+
+exit "$RTN"
diff --git a/.kokoro/test-samples.sh b/.kokoro/test-samples.sh
index cdf5d4e32..421439bc8 100755
--- a/.kokoro/test-samples.sh
+++ b/.kokoro/test-samples.sh
@@ -13,6 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# The default test runner for samples.
+#
+# For periodic builds, we rewinds the repo to the latest release, and
+# run test-samples-impl.sh.
 
 # `-e` enables the script to automatically fail when a command fails
 # `-o pipefail` sets the exit code to the rightmost comment to exit with a non-zero
@@ -24,81 +28,19 @@ cd github/python-storage
 
 # Run periodic samples tests at latest release
 if [[ $KOKORO_BUILD_ARTIFACTS_SUBDIR = *"periodic"* ]]; then
+    # preserving the test runner implementation.
+    cp .kokoro/test-samples-impl.sh "${TMPDIR}/test-samples-impl.sh"
+    echo "--- IMPORTANT IMPORTANT IMPORTANT ---"
+    echo "Now we rewind the repo back to the latest release..."
     LATEST_RELEASE=$(git describe --abbrev=0 --tags)
     git checkout $LATEST_RELEASE
-fi
-
-# Disable buffering, so that the logs stream through.
-export PYTHONUNBUFFERED=1
-
-# Debug: show build environment
-env | grep KOKORO
-
-# Install nox
-python3.6 -m pip install --upgrade --quiet nox
-
-# Use secrets acessor service account to get secrets
-if [[ -f "${KOKORO_GFILE_DIR}/secrets_viewer_service_account.json" ]]; then
-    gcloud auth activate-service-account \
-	   --key-file="${KOKORO_GFILE_DIR}/secrets_viewer_service_account.json" \
-	   --project="cloud-devrel-kokoro-resources"
-fi
-
-# This script will create 3 files:
-# - testing/test-env.sh
-# - testing/service-account.json
-# - testing/client-secrets.json
-./scripts/decrypt-secrets.sh
-
-source ./testing/test-env.sh
-export GOOGLE_APPLICATION_CREDENTIALS=$(pwd)/testing/service-account.json
-
-# For cloud-run session, we activate the service account for gcloud sdk.
-gcloud auth activate-service-account \
-       --key-file "${GOOGLE_APPLICATION_CREDENTIALS}"
-
-export GOOGLE_CLIENT_SECRETS=$(pwd)/testing/client-secrets.json
-
-echo -e "\n******************** TESTING PROJECTS ********************"
-
-# Switch to 'fail at end' to allow all tests to complete before exiting.
-set +e
-# Use RTN to return a non-zero value if the test fails.
-RTN=0
-ROOT=$(pwd)
-# Find all requirements.txt in the samples directory (may break on whitespace).
-for file in samples/**/requirements.txt; do
-    cd "$ROOT"
-    # Navigate to the project folder.
-    file=$(dirname "$file")
-    cd "$file"
-
-    echo "------------------------------------------------------------"
-    echo "- testing $file"
-    echo "------------------------------------------------------------"
-
-    # Use nox to execute the tests for the project.
-    python3.6 -m nox -s "$RUN_TESTS_SESSION"
-    EXIT=$?
-
-    # If this is a periodic build, send the test log to the FlakyBot.
-    # See https://github.com/googleapis/repo-automation-bots/tree/master/packages/flakybot.
-    if [[ $KOKORO_BUILD_ARTIFACTS_SUBDIR = *"periodic"* ]]; then
-      chmod +x $KOKORO_GFILE_DIR/linux_amd64/flakybot
-      $KOKORO_GFILE_DIR/linux_amd64/flakybot
+    echo "The current head is: "
+    echo $(git rev-parse --verify HEAD)
+    echo "--- IMPORTANT IMPORTANT IMPORTANT ---"
+    # move back the test runner implementation if there's no file.
+    if [ ! -f .kokoro/test-samples-impl.sh ]; then
+	cp "${TMPDIR}/test-samples-impl.sh" .kokoro/test-samples-impl.sh
     fi
+fi
 
-    if [[ $EXIT -ne 0 ]]; then
-      RTN=1
-      echo -e "\n Testing failed: Nox returned a non-zero exit code. \n"
-    else
-      echo -e "\n Testing completed.\n"
-    fi
-
-done
-cd "$ROOT"
-
-# Workaround for Kokoro permissions issue: delete secrets
-rm testing/{test-env.sh,client-secrets.json,service-account.json}
-
-exit "$RTN"
\ No newline at end of file
+exec .kokoro/test-samples-impl.sh
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 2a87c6d4d..32302e488 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -12,6 +12,6 @@ repos:
     hooks:
     - id: black
 -   repo: https://gitlab.com/pycqa/flake8
-    rev: 3.9.1
+    rev: 3.9.0
     hooks:
     - id: flake8
diff --git a/.trampolinerc b/.trampolinerc
index 995ee2911..383b6ec89 100644
--- a/.trampolinerc
+++ b/.trampolinerc
@@ -24,6 +24,7 @@ required_envvars+=(
 pass_down_envvars+=(
     "STAGING_BUCKET"
     "V2_STAGING_BUCKET"
+    "NOX_SESSION"
 )
 
 # Prevent unintentional override on the default image.
diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
index b3d1f6029..039f43681 100644
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -1,44 +1,95 @@
 <!-- # Generated by synthtool. DO NOT EDIT! !-->
-# Contributor Code of Conduct
+# Code of Conduct
 
-As contributors and maintainers of this project,
-and in the interest of fostering an open and welcoming community,
-we pledge to respect all people who contribute through reporting issues,
-posting feature requests, updating documentation,
-submitting pull requests or patches, and other activities.
+## Our Pledge
 
-We are committed to making participation in this project
-a harassment-free experience for everyone,
-regardless of level of experience, gender, gender identity and expression,
-sexual orientation, disability, personal appearance,
-body size, race, ethnicity, age, religion, or nationality.
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, gender identity and expression, level of
+experience, education, socio-economic status, nationality, personal appearance,
+race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+*   Using welcoming and inclusive language
+*   Being respectful of differing viewpoints and experiences
+*   Gracefully accepting constructive criticism
+*   Focusing on what is best for the community
+*   Showing empathy towards other community members
 
 Examples of unacceptable behavior by participants include:
 
-* The use of sexualized language or imagery
-* Personal attacks
-* Trolling or insulting/derogatory comments
-* Public or private harassment
-* Publishing other's private information,
-such as physical or electronic
-addresses, without explicit permission
-* Other unethical or unprofessional conduct.
+*   The use of sexualized language or imagery and unwelcome sexual attention or
+    advances
+*   Trolling, insulting/derogatory comments, and personal or political attacks
+*   Public or private harassment
+*   Publishing others' private information, such as a physical or electronic
+    address, without explicit permission
+*   Other conduct which could reasonably be considered inappropriate in a
+    professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
 
 Project maintainers have the right and responsibility to remove, edit, or reject
-comments, commits, code, wiki edits, issues, and other contributions
-that are not aligned to this Code of Conduct.
-By adopting this Code of Conduct,
-project maintainers commit themselves to fairly and consistently
-applying these principles to every aspect of managing this project.
-Project maintainers who do not follow or enforce the Code of Conduct
-may be permanently removed from the project team.
-
-This code of conduct applies both within project spaces and in public spaces
-when an individual is representing the project or its community.
-
-Instances of abusive, harassing, or otherwise unacceptable behavior
-may be reported by opening an issue
-or contacting one or more of the project maintainers.
-
-This Code of Conduct is adapted from the [Contributor Covenant](http://contributor-covenant.org), version 1.2.0,
-available at [http://contributor-covenant.org/version/1/2/0/](http://contributor-covenant.org/version/1/2/0/)
+comments, commits, code, wiki edits, issues, and other contributions that are
+not aligned to this Code of Conduct, or to ban temporarily or permanently any
+contributor for other behaviors that they deem inappropriate, threatening,
+offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
+
+This Code of Conduct also applies outside the project spaces when the Project
+Steward has a reasonable belief that an individual's behavior may have a
+negative impact on the project or its community.
+
+## Conflict Resolution
+
+We do not believe that all conflict is bad; healthy debate and disagreement
+often yield positive results. However, it is never okay to be disrespectful or
+to engage in behavior that violates the project’s code of conduct.
+
+If you see someone violating the code of conduct, you are encouraged to address
+the behavior directly with those involved. Many issues can be resolved quickly
+and easily, and this gives people more control over the outcome of their
+dispute. If you are unable to resolve the matter for any reason, or if the
+behavior is threatening or harassing, report it. We are dedicated to providing
+an environment where participants feel welcome and safe.
+
+
+Reports should be directed to *googleapis-stewards@google.com*, the
+Project Steward(s) for *Google Cloud Client Libraries*. It is the Project Steward’s duty to
+receive and address reported violations of the code of conduct. They will then
+work with a committee consisting of representatives from the Open Source
+Programs Office and the Google Open Source Strategy team. If for any reason you
+are uncomfortable reaching out to the Project Steward, please email
+opensource@google.com.
+
+We will investigate every complaint, but you may not receive a direct response.
+We will use our discretion in determining when and how to follow up on reported
+incidents, which may range from not taking action to permanent expulsion from
+the project and project-sponsored spaces. We will notify the accused of the
+report and provide them an opportunity to discuss it before any action is taken.
+The identity of the reporter will be omitted from the details of the report
+supplied to the accused. In potentially harmful situations, such as ongoing
+harassment or threats to anyone's safety, we may take action without notice.
+
+## Attribution
+
+This Code of Conduct is adapted from the Contributor Covenant, version 1.4,
+available at
+https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
\ No newline at end of file
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index 5d766a94a..b5ce8f8d7 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -21,8 +21,8 @@ In order to add a feature:
 - The feature must be documented in both the API and narrative
   documentation.
 
-- The feature must work fully on the following CPython versions:  2.7,
-  3.5, 3.6, 3.7 and 3.8 on both UNIX and Windows.
+- The feature must work fully on the following CPython versions:
+  3.6, 3.7, 3.8 and 3.9 on both UNIX and Windows.
 
 - The feature must not add unnecessary dependencies (where
   "unnecessary" is of course subjective, but new dependencies should
@@ -70,9 +70,14 @@ We use `nox <https://nox.readthedocs.io/en/latest/>`__ to instrument our tests.
 - To test your changes, run unit tests with ``nox``::
 
     $ nox -s unit-2.7
-    $ nox -s unit-3.7
+    $ nox -s unit-3.8
     $ ...
 
+- Args to pytest can be passed through the nox command separated by a `--`. For
+  example, to run a single test::
+
+    $ nox -s unit-3.8 -- -k <name of test>
+
   .. note::
 
     The unit tests and system tests are described in the
@@ -93,8 +98,12 @@ On Debian/Ubuntu::
 ************
 Coding Style
 ************
+- We use the automatic code formatter ``black``. You can run it using
+  the nox session ``blacken``. This will eliminate many lint errors. Run via::
+
+   $ nox -s blacken
 
-- PEP8 compliance, with exceptions defined in the linter configuration.
+- PEP8 compliance is required, with exceptions defined in the linter configuration.
   If you have ``nox`` installed, you can test that you have not introduced
   any non-compliant code via::
 
@@ -111,7 +120,7 @@ Coding Style
   should point to the official ``googleapis`` checkout and the
   the branch should be the main branch on that remote (``master``).
 
-- This repository contains configuration for the 
+- This repository contains configuration for the
   `pre-commit <https://pre-commit.com/>`__ tool, which automates checking
   our linters during a commit.  If you have it installed on your ``$PATH``,
   you can enable enforcing those checks via:
@@ -133,13 +142,18 @@ Running System Tests
 
 - To run system tests, you can execute::
 
-   $ nox -s system-3.7
+   # Run all system tests
+   $ nox -s system-3.8
    $ nox -s system-2.7
 
+   # Run a single system test
+   $ nox -s system-3.8 -- -k <name of test>
+
+
   .. note::
 
       System tests are only configured to run under Python 2.7 and
-      Python 3.7. For expediency, we do not run them in older versions
+      Python 3.8. For expediency, we do not run them in older versions
       of Python 3.
 
   This alone will not run the tests. You'll need to change some local
@@ -202,25 +216,24 @@ Supported Python Versions
 
 We support:
 
--  `Python 3.5`_
 -  `Python 3.6`_
 -  `Python 3.7`_
 -  `Python 3.8`_
+-  `Python 3.9`_
 
-.. _Python 3.5: https://docs.python.org/3.5/
 .. _Python 3.6: https://docs.python.org/3.6/
 .. _Python 3.7: https://docs.python.org/3.7/
 .. _Python 3.8: https://docs.python.org/3.8/
+.. _Python 3.9: https://docs.python.org/3.9/
 
 
 Supported versions can be found in our ``noxfile.py`` `config`_.
 
 .. _config: https://github.com/googleapis/python-storage/blob/master/noxfile.py
 
-Python 2.7 support is deprecated. All code changes should maintain Python 2.7 compatibility until January 1, 2020.
 
 We also explicitly decided to support Python 3 beginning with version
-3.5. Reasons for this include:
+3.6. Reasons for this include:
 
 -  Encouraging use of newest versions of Python 3
 -  Taking the lead of `prominent`_ open-source `projects`_
diff --git a/LICENSE b/LICENSE
index a8ee855de..d64569567 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,7 @@
-                            Apache License
+
+                                 Apache License
                            Version 2.0, January 2004
-                        https://www.apache.org/licenses/
+                        http://www.apache.org/licenses/
 
    TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
 
@@ -192,7 +193,7 @@
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at
 
-       https://www.apache.org/licenses/LICENSE-2.0
+       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,
diff --git a/MANIFEST.in b/MANIFEST.in
index e9e29d120..e783f4c62 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -16,10 +16,10 @@
 
 # Generated by synthtool. DO NOT EDIT!
 include README.rst LICENSE
-recursive-include google *.json *.proto
+recursive-include google *.json *.proto py.typed
 recursive-include tests *
 global-exclude *.py[co]
 global-exclude __pycache__
 
 # Exclude scripts for samples readmegen
-prune scripts/readme-gen
\ No newline at end of file
+prune scripts/readme-gen
diff --git a/docs/_static/custom.css b/docs/_static/custom.css
index 0abaf229f..bcd37bbd3 100644
--- a/docs/_static/custom.css
+++ b/docs/_static/custom.css
@@ -1,4 +1,9 @@
 div#python2-eol {
 	border-color: red;
 	border-width: medium;
-} 
\ No newline at end of file
+} 
+
+/* Ensure minimum width for 'Parameters' / 'Returns' column */
+dl.field-list > dt {
+    min-width: 100px
+}
diff --git a/docs/conf.py b/docs/conf.py
index 858ffec80..f4f0a42ab 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -345,10 +345,11 @@
 
 # Example configuration for intersphinx: refer to the Python standard library.
 intersphinx_mapping = {
-    "python": ("http://python.readthedocs.org/en/latest/", None),
-    "google-auth": ("https://google-auth.readthedocs.io/en/stable", None),
+    "python": ("https://python.readthedocs.org/en/latest/", None),
+    "google-auth": ("https://googleapis.dev/python/google-auth/latest/", None),
     "google.api_core": ("https://googleapis.dev/python/google-api-core/latest/", None,),
-    "grpc": ("https://grpc.io/grpc/python/", None),
+    "grpc": ("https://grpc.github.io/grpc/python/", None),
+    "proto-plus": ("https://proto-plus-python.readthedocs.io/en/latest/", None),
 }
 
 
diff --git a/noxfile.py b/noxfile.py
index 5f3f73ebb..b72dfe135 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -18,6 +18,7 @@
 
 from __future__ import absolute_import
 import os
+import pathlib
 import shutil
 
 import nox
@@ -30,6 +31,22 @@
 SYSTEM_TEST_PYTHON_VERSIONS = ["2.7", "3.8"]
 UNIT_TEST_PYTHON_VERSIONS = ["2.7", "3.6", "3.7", "3.8", "3.9"]
 
+CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
+
+# 'docfx' is excluded since it only needs to run in 'docs-presubmit'
+nox.options.sessions = [
+    "unit",
+    "system",
+    "cover",
+    "lint",
+    "lint_setup_py",
+    "blacken",
+    "docs",
+]
+
+# Error if a python version is missing
+nox.options.error_on_missing_interpreters = True
+
 
 @nox.session(python=DEFAULT_PYTHON_VERSION)
 def lint(session):
@@ -70,16 +87,21 @@ def lint_setup_py(session):
 
 def default(session):
     # Install all test dependencies, then install this package in-place.
-    session.install("mock", "pytest", "pytest-cov")
-    session.install("-e", ".")
+
+    constraints_path = str(
+        CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
+    )
+    session.install("mock", "pytest", "pytest-cov", "-c", constraints_path)
+
+    session.install("-e", ".", "-c", constraints_path)
 
     # Run py.test against the unit tests.
     session.run(
         "py.test",
         "--quiet",
-        "--cov=google.cloud.storage",
-        "--cov=google.cloud",
-        "--cov=tests.unit",
+        f"--junitxml=unit_{session.python}_sponge_log.xml",
+        "--cov=google/cloud",
+        "--cov=tests/unit",
         "--cov-append",
         "--cov-config=.coveragerc",
         "--cov-report=",
@@ -98,22 +120,25 @@ def unit(session):
 @nox.session(python=SYSTEM_TEST_PYTHON_VERSIONS)
 def system(session):
     """Run the system test suite."""
+    constraints_path = str(
+        CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
+    )
     system_test_path = os.path.join("tests", "system.py")
     system_test_folder_path = os.path.join("tests", "system")
 
     # Check the value of `RUN_SYSTEM_TESTS` env var. It defaults to true.
     if os.environ.get("RUN_SYSTEM_TESTS", "true") == "false":
         session.skip("RUN_SYSTEM_TESTS is set to false, skipping")
-    # Environment check: Only run tests if the environment variable is set.
+    # Sanity check: Only run tests if the environment variable is set.
     if not os.environ.get("GOOGLE_APPLICATION_CREDENTIALS", ""):
         session.skip("Credentials must be set via environment variable")
-    # mTLS tests requires pyopenssl.
-    if os.environ.get("GOOGLE_API_USE_CLIENT_CERTIFICATE", "") == "true":
+    # Install pyopenssl for mTLS testing.
+    if os.environ.get("GOOGLE_API_USE_CLIENT_CERTIFICATE", "false") == "true":
         session.install("pyopenssl")
 
     system_test_exists = os.path.exists(system_test_path)
     system_test_folder_exists = os.path.exists(system_test_folder_path)
-    # Environment check: only run tests if found.
+    # Sanity check: only run tests if found.
     if not system_test_exists and not system_test_folder_exists:
         session.skip("System tests were not found")
 
@@ -129,14 +154,28 @@ def system(session):
         "google-cloud-iam",
         "google-cloud-pubsub < 2.0.0",
         "google-cloud-kms < 2.0dev",
+        "-c",
+        constraints_path,
     )
-    session.install("-e", ".")
+    session.install("-e", ".", "-c", constraints_path)
 
     # Run py.test against the system tests.
     if system_test_exists:
-        session.run("py.test", "--quiet", system_test_path, *session.posargs)
+        session.run(
+            "py.test",
+            "--quiet",
+            f"--junitxml=system_{session.python}_sponge_log.xml",
+            system_test_path,
+            *session.posargs,
+        )
     if system_test_folder_exists:
-        session.run("py.test", "--quiet", system_test_folder_path, *session.posargs)
+        session.run(
+            "py.test",
+            "--quiet",
+            f"--junitxml=system_{session.python}_sponge_log.xml",
+            system_test_folder_path,
+            *session.posargs,
+        )
 
 
 @nox.session(python=DEFAULT_PYTHON_VERSION)
@@ -179,9 +218,7 @@ def docfx(session):
     """Build the docfx yaml files for this library."""
 
     session.install("-e", ".")
-    # sphinx-docfx-yaml supports up to sphinx version 1.5.5.
-    # https://github.com/docascode/sphinx-docfx-yaml/issues/97
-    session.install("sphinx==1.5.5", "alabaster", "recommonmark", "sphinx-docfx-yaml")
+    session.install("sphinx", "alabaster", "recommonmark", "gcp-sphinx-docfx-yaml")
 
     shutil.rmtree(os.path.join("docs", "_build"), ignore_errors=True)
     session.run(
diff --git a/synth.py b/owlbot.py
similarity index 100%
rename from synth.py
rename to owlbot.py
diff --git a/renovate.json b/renovate.json
index 4fa949311..f08bc22c9 100644
--- a/renovate.json
+++ b/renovate.json
@@ -1,5 +1,6 @@
 {
   "extends": [
     "config:base",  ":preserveSemverRanges"
-  ]
+  ],
+  "ignorePaths": [".pre-commit-config.yaml"]
 }
diff --git a/synth.metadata b/synth.metadata
deleted file mode 100644
index 7fdf91454..000000000
--- a/synth.metadata
+++ /dev/null
@@ -1,83 +0,0 @@
-{
-  "sources": [
-    {
-      "git": {
-        "name": ".",
-        "remote": "https://github.com/googleapis/python-storage.git",
-        "sha": "dc3671963f25dde7ba393c8e3939225b5c61d158"
-      }
-    },
-    {
-      "git": {
-        "name": "synthtool",
-        "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "f3c04883d6c43261ff13db1f52d03a283be06871"
-      }
-    }
-  ],
-  "generatedFiles": [
-    ".coveragerc",
-    ".flake8",
-    ".github/CONTRIBUTING.md",
-    ".github/ISSUE_TEMPLATE/bug_report.md",
-    ".github/ISSUE_TEMPLATE/feature_request.md",
-    ".github/ISSUE_TEMPLATE/support_request.md",
-    ".github/PULL_REQUEST_TEMPLATE.md",
-    ".github/release-please.yml",
-    ".github/snippet-bot.yml",
-    ".gitignore",
-    ".kokoro/build.sh",
-    ".kokoro/continuous/common.cfg",
-    ".kokoro/continuous/continuous.cfg",
-    ".kokoro/docker/docs/Dockerfile",
-    ".kokoro/docker/docs/fetch_gpg_keys.sh",
-    ".kokoro/docs/common.cfg",
-    ".kokoro/docs/docs-presubmit.cfg",
-    ".kokoro/docs/docs.cfg",
-    ".kokoro/populate-secrets.sh",
-    ".kokoro/presubmit/common.cfg",
-    ".kokoro/presubmit/presubmit.cfg",
-    ".kokoro/publish-docs.sh",
-    ".kokoro/release.sh",
-    ".kokoro/release/common.cfg",
-    ".kokoro/release/release.cfg",
-    ".kokoro/samples/lint/common.cfg",
-    ".kokoro/samples/lint/continuous.cfg",
-    ".kokoro/samples/lint/periodic.cfg",
-    ".kokoro/samples/lint/presubmit.cfg",
-    ".kokoro/samples/python3.6/common.cfg",
-    ".kokoro/samples/python3.6/continuous.cfg",
-    ".kokoro/samples/python3.6/periodic.cfg",
-    ".kokoro/samples/python3.6/presubmit.cfg",
-    ".kokoro/samples/python3.7/common.cfg",
-    ".kokoro/samples/python3.7/continuous.cfg",
-    ".kokoro/samples/python3.7/periodic.cfg",
-    ".kokoro/samples/python3.7/presubmit.cfg",
-    ".kokoro/samples/python3.8/common.cfg",
-    ".kokoro/samples/python3.8/continuous.cfg",
-    ".kokoro/samples/python3.8/periodic.cfg",
-    ".kokoro/samples/python3.8/presubmit.cfg",
-    ".kokoro/test-samples.sh",
-    ".kokoro/trampoline.sh",
-    ".kokoro/trampoline_v2.sh",
-    ".trampolinerc",
-    "CODE_OF_CONDUCT.md",
-    "CONTRIBUTING.rst",
-    "LICENSE",
-    "MANIFEST.in",
-    "docs/_static/custom.css",
-    "docs/_templates/layout.html",
-    "docs/conf.py",
-    "noxfile.py",
-    "renovate.json",
-    "scripts/decrypt-secrets.sh",
-    "scripts/readme-gen/readme_gen.py",
-    "scripts/readme-gen/templates/README.tmpl.rst",
-    "scripts/readme-gen/templates/auth.tmpl.rst",
-    "scripts/readme-gen/templates/auth_api_key.tmpl.rst",
-    "scripts/readme-gen/templates/install_deps.tmpl.rst",
-    "scripts/readme-gen/templates/install_portaudio.tmpl.rst",
-    "setup.cfg",
-    "testing/.gitignore"
-  ]
-}
\ No newline at end of file
diff --git a/testing/constraints-2.7.txt b/testing/constraints-2.7.txt
new file mode 100644
index 000000000..1dc85f7a7
--- /dev/null
+++ b/testing/constraints-2.7.txt
@@ -0,0 +1,11 @@
+# This constraints file is used to check that lower bounds
+# are correct in setup.py
+# List *all* library dependencies and extras in this file.
+# Pin the version to the lower bound.
+#
+# e.g., if setup.py has "foo >= 1.14.0, < 2.0.0dev",
+# Then this file should have foo==1.14.0
+google-auth==1.11.0
+google-cloud-core==1.4.1
+google-resumable-media==1.0.0
+requests==2.18.0