diff --git a/.github/.OwlBot.lock.yaml b/.github/.OwlBot.lock.yaml
index 7d98291..108063d 100644
--- a/.github/.OwlBot.lock.yaml
+++ b/.github/.OwlBot.lock.yaml
@@ -1,3 +1,3 @@
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:58f73ba196b5414782605236dd0712a73541b44ff2ff4d3a36ec41092dd6fa5b
+  digest: sha256:4ee57a76a176ede9087c14330c625a71553cf9c72828b2c0ca12f5338171ba60
diff --git a/.kokoro/docs/common.cfg b/.kokoro/docs/common.cfg
index 4365360..6701ad1 100644
--- a/.kokoro/docs/common.cfg
+++ b/.kokoro/docs/common.cfg
@@ -30,6 +30,7 @@ env_vars: {
 
 env_vars: {
     key: "V2_STAGING_BUCKET"
+    # Push google cloud library docs to the Cloud RAD bucket `docs-staging-v2`
     value: "docs-staging-v2"
 }
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index dbf4419..4e456b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,18 @@
 # Changelog
 
+### [1.3.1](https://www.github.com/googleapis/python-bigquery-connection/compare/v1.3.0...v1.3.1) (2021-11-02)
+
+
+### Bug Fixes
+
+* **deps:** drop packaging dependency ([826da22](https://www.github.com/googleapis/python-bigquery-connection/commit/826da22f591ab1c16eadf3a53cc8476e04577f40))
+* **deps:** require google-api-core >= 1.28.0 ([826da22](https://www.github.com/googleapis/python-bigquery-connection/commit/826da22f591ab1c16eadf3a53cc8476e04577f40))
+
+
+### Documentation
+
+* list oneofs in docstring ([826da22](https://www.github.com/googleapis/python-bigquery-connection/commit/826da22f591ab1c16eadf3a53cc8476e04577f40))
+
 ## [1.3.0](https://www.github.com/googleapis/python-bigquery-connection/compare/v1.2.3...v1.3.0) (2021-10-08)
 
 
diff --git a/docs/index.rst b/docs/index.rst
index 944bf8d..3e3f392 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -1,6 +1,8 @@
 .. include:: README.rst
+
 .. include:: multiprocessing.rst
 
+
 API Reference
 -------------
 .. toctree::
@@ -9,12 +11,13 @@ API Reference
     bigquery_connection_v1/services
     bigquery_connection_v1/types
 
+
 Changelog
 ---------
 
 For a list of all ``google-cloud-bigquery-connection`` releases:
 
 .. toctree::
-   :maxdepth: 2
+    :maxdepth: 2
 
-   changelog
+    changelog
diff --git a/google/cloud/bigquery_connection_v1/services/connection_service/async_client.py b/google/cloud/bigquery_connection_v1/services/connection_service/async_client.py
index b5b09f5..467ed46 100644
--- a/google/cloud/bigquery_connection_v1/services/connection_service/async_client.py
+++ b/google/cloud/bigquery_connection_v1/services/connection_service/async_client.py
@@ -19,13 +19,15 @@
 from typing import Dict, Sequence, Tuple, Type, Union
 import pkg_resources
 
-import google.api_core.client_options as ClientOptions  # type: ignore
+from google.api_core.client_options import ClientOptions  # type: ignore
 from google.api_core import exceptions as core_exceptions  # type: ignore
 from google.api_core import gapic_v1  # type: ignore
 from google.api_core import retry as retries  # type: ignore
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.oauth2 import service_account  # type: ignore
 
+OptionalRetry = Union[retries.Retry, object]
+
 from google.cloud.bigquery_connection_v1.services.connection_service import pagers
 from google.cloud.bigquery_connection_v1.types import connection
 from google.cloud.bigquery_connection_v1.types import connection as gcbc_connection
@@ -167,19 +169,19 @@ def __init__(
 
     async def create_connection(
         self,
-        request: gcbc_connection.CreateConnectionRequest = None,
+        request: Union[gcbc_connection.CreateConnectionRequest, dict] = None,
         *,
         parent: str = None,
         connection: gcbc_connection.Connection = None,
         connection_id: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> gcbc_connection.Connection:
         r"""Creates a new connection.
 
         Args:
-            request (:class:`google.cloud.bigquery_connection_v1.types.CreateConnectionRequest`):
+            request (Union[google.cloud.bigquery_connection_v1.types.CreateConnectionRequest, dict]):
                 The request object. The request for
                 [ConnectionService.CreateConnection][google.cloud.bigquery.connection.v1.ConnectionService.CreateConnection].
             parent (:class:`str`):
@@ -257,17 +259,17 @@ async def create_connection(
 
     async def get_connection(
         self,
-        request: connection.GetConnectionRequest = None,
+        request: Union[connection.GetConnectionRequest, dict] = None,
         *,
         name: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> connection.Connection:
         r"""Returns specified connection.
 
         Args:
-            request (:class:`google.cloud.bigquery_connection_v1.types.GetConnectionRequest`):
+            request (Union[google.cloud.bigquery_connection_v1.types.GetConnectionRequest, dict]):
                 The request object. The request for
                 [ConnectionService.GetConnection][google.cloud.bigquery.connection.v1.ConnectionService.GetConnection].
             name (:class:`str`):
@@ -339,17 +341,17 @@ async def get_connection(
 
     async def list_connections(
         self,
-        request: connection.ListConnectionsRequest = None,
+        request: Union[connection.ListConnectionsRequest, dict] = None,
         *,
         parent: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pagers.ListConnectionsAsyncPager:
         r"""Returns a list of connections in the given project.
 
         Args:
-            request (:class:`google.cloud.bigquery_connection_v1.types.ListConnectionsRequest`):
+            request (Union[google.cloud.bigquery_connection_v1.types.ListConnectionsRequest, dict]):
                 The request object. The request for
                 [ConnectionService.ListConnections][google.cloud.bigquery.connection.v1.ConnectionService.ListConnections].
             parent (:class:`str`):
@@ -429,12 +431,12 @@ async def list_connections(
 
     async def update_connection(
         self,
-        request: gcbc_connection.UpdateConnectionRequest = None,
+        request: Union[gcbc_connection.UpdateConnectionRequest, dict] = None,
         *,
         name: str = None,
         connection: gcbc_connection.Connection = None,
         update_mask: field_mask_pb2.FieldMask = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> gcbc_connection.Connection:
@@ -443,7 +445,7 @@ async def update_connection(
         are in the update field mask.
 
         Args:
-            request (:class:`google.cloud.bigquery_connection_v1.types.UpdateConnectionRequest`):
+            request (Union[google.cloud.bigquery_connection_v1.types.UpdateConnectionRequest, dict]):
                 The request object. The request for
                 [ConnectionService.UpdateConnection][google.cloud.bigquery.connection.v1.ConnectionService.UpdateConnection].
             name (:class:`str`):
@@ -523,17 +525,17 @@ async def update_connection(
 
     async def delete_connection(
         self,
-        request: connection.DeleteConnectionRequest = None,
+        request: Union[connection.DeleteConnectionRequest, dict] = None,
         *,
         name: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
         r"""Deletes connection and associated credential.
 
         Args:
-            request (:class:`google.cloud.bigquery_connection_v1.types.DeleteConnectionRequest`):
+            request (Union[google.cloud.bigquery_connection_v1.types.DeleteConnectionRequest, dict]):
                 The request object. The request for
                 [ConnectionService.DeleteConnectionRequest][].
             name (:class:`str`):
@@ -597,10 +599,10 @@ async def delete_connection(
 
     async def get_iam_policy(
         self,
-        request: iam_policy_pb2.GetIamPolicyRequest = None,
+        request: Union[iam_policy_pb2.GetIamPolicyRequest, dict] = None,
         *,
         resource: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
@@ -609,7 +611,7 @@ async def get_iam_policy(
         not have a policy set.
 
         Args:
-            request (:class:`google.iam.v1.iam_policy_pb2.GetIamPolicyRequest`):
+            request (Union[google.iam.v1.iam_policy_pb2.GetIamPolicyRequest, dict]):
                 The request object. Request message for `GetIamPolicy`
                 method.
             resource (:class:`str`):
@@ -725,10 +727,10 @@ async def get_iam_policy(
 
     async def set_iam_policy(
         self,
-        request: iam_policy_pb2.SetIamPolicyRequest = None,
+        request: Union[iam_policy_pb2.SetIamPolicyRequest, dict] = None,
         *,
         resource: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
@@ -739,7 +741,7 @@ async def set_iam_policy(
         ``PERMISSION_DENIED`` errors.
 
         Args:
-            request (:class:`google.iam.v1.iam_policy_pb2.SetIamPolicyRequest`):
+            request (Union[google.iam.v1.iam_policy_pb2.SetIamPolicyRequest, dict]):
                 The request object. Request message for `SetIamPolicy`
                 method.
             resource (:class:`str`):
@@ -855,11 +857,11 @@ async def set_iam_policy(
 
     async def test_iam_permissions(
         self,
-        request: iam_policy_pb2.TestIamPermissionsRequest = None,
+        request: Union[iam_policy_pb2.TestIamPermissionsRequest, dict] = None,
         *,
         resource: str = None,
         permissions: Sequence[str] = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> iam_policy_pb2.TestIamPermissionsResponse:
@@ -873,7 +875,7 @@ async def test_iam_permissions(
         warning.
 
         Args:
-            request (:class:`google.iam.v1.iam_policy_pb2.TestIamPermissionsRequest`):
+            request (Union[google.iam.v1.iam_policy_pb2.TestIamPermissionsRequest, dict]):
                 The request object. Request message for
                 `TestIamPermissions` method.
             resource (:class:`str`):
diff --git a/google/cloud/bigquery_connection_v1/services/connection_service/client.py b/google/cloud/bigquery_connection_v1/services/connection_service/client.py
index fa3473c..9337bf5 100644
--- a/google/cloud/bigquery_connection_v1/services/connection_service/client.py
+++ b/google/cloud/bigquery_connection_v1/services/connection_service/client.py
@@ -30,6 +30,8 @@
 from google.auth.exceptions import MutualTLSChannelError  # type: ignore
 from google.oauth2 import service_account  # type: ignore
 
+OptionalRetry = Union[retries.Retry, object]
+
 from google.cloud.bigquery_connection_v1.services.connection_service import pagers
 from google.cloud.bigquery_connection_v1.types import connection
 from google.cloud.bigquery_connection_v1.types import connection as gcbc_connection
@@ -360,7 +362,7 @@ def create_connection(
         parent: str = None,
         connection: gcbc_connection.Connection = None,
         connection_id: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> gcbc_connection.Connection:
@@ -448,7 +450,7 @@ def get_connection(
         request: Union[connection.GetConnectionRequest, dict] = None,
         *,
         name: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> connection.Connection:
@@ -520,7 +522,7 @@ def list_connections(
         request: Union[connection.ListConnectionsRequest, dict] = None,
         *,
         parent: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> pagers.ListConnectionsPager:
@@ -602,7 +604,7 @@ def update_connection(
         name: str = None,
         connection: gcbc_connection.Connection = None,
         update_mask: field_mask_pb2.FieldMask = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> gcbc_connection.Connection:
@@ -694,7 +696,7 @@ def delete_connection(
         request: Union[connection.DeleteConnectionRequest, dict] = None,
         *,
         name: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> None:
@@ -758,7 +760,7 @@ def get_iam_policy(
         request: Union[iam_policy_pb2.GetIamPolicyRequest, dict] = None,
         *,
         resource: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
@@ -885,7 +887,7 @@ def set_iam_policy(
         request: Union[iam_policy_pb2.SetIamPolicyRequest, dict] = None,
         *,
         resource: str = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> policy_pb2.Policy:
@@ -1015,7 +1017,7 @@ def test_iam_permissions(
         *,
         resource: str = None,
         permissions: Sequence[str] = None,
-        retry: retries.Retry = gapic_v1.method.DEFAULT,
+        retry: OptionalRetry = gapic_v1.method.DEFAULT,
         timeout: float = None,
         metadata: Sequence[Tuple[str, str]] = (),
     ) -> iam_policy_pb2.TestIamPermissionsResponse:
diff --git a/google/cloud/bigquery_connection_v1/services/connection_service/transports/base.py b/google/cloud/bigquery_connection_v1/services/connection_service/transports/base.py
index 2bd9d67..30e64ec 100644
--- a/google/cloud/bigquery_connection_v1/services/connection_service/transports/base.py
+++ b/google/cloud/bigquery_connection_v1/services/connection_service/transports/base.py
@@ -15,7 +15,6 @@
 #
 import abc
 from typing import Awaitable, Callable, Dict, Optional, Sequence, Union
-import packaging.version
 import pkg_resources
 
 import google.auth  # type: ignore
@@ -41,15 +40,6 @@
 except pkg_resources.DistributionNotFound:
     DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo()
 
-try:
-    # google.auth.__version__ was added in 1.26.0
-    _GOOGLE_AUTH_VERSION = google.auth.__version__
-except AttributeError:
-    try:  # try pkg_resources if it is available
-        _GOOGLE_AUTH_VERSION = pkg_resources.get_distribution("google-auth").version
-    except pkg_resources.DistributionNotFound:  # pragma: NO COVER
-        _GOOGLE_AUTH_VERSION = None
-
 
 class ConnectionServiceTransport(abc.ABC):
     """Abstract transport class for ConnectionService."""
@@ -102,7 +92,7 @@ def __init__(
             host += ":443"
         self._host = host
 
-        scopes_kwargs = self._get_scopes_kwargs(self._host, scopes)
+        scopes_kwargs = {"scopes": scopes, "default_scopes": self.AUTH_SCOPES}
 
         # Save the scopes.
         self._scopes = scopes
@@ -135,29 +125,6 @@ def __init__(
         # Save the credentials.
         self._credentials = credentials
 
-    # TODO(busunkim): This method is in the base transport
-    # to avoid duplicating code across the transport classes. These functions
-    # should be deleted once the minimum required versions of google-auth is increased.
-
-    # TODO: Remove this function once google-auth >= 1.25.0 is required
-    @classmethod
-    def _get_scopes_kwargs(
-        cls, host: str, scopes: Optional[Sequence[str]]
-    ) -> Dict[str, Optional[Sequence[str]]]:
-        """Returns scopes kwargs to pass to google-auth methods depending on the google-auth version"""
-
-        scopes_kwargs = {}
-
-        if _GOOGLE_AUTH_VERSION and (
-            packaging.version.parse(_GOOGLE_AUTH_VERSION)
-            >= packaging.version.parse("1.25.0")
-        ):
-            scopes_kwargs = {"scopes": scopes, "default_scopes": cls.AUTH_SCOPES}
-        else:
-            scopes_kwargs = {"scopes": scopes or cls.AUTH_SCOPES}
-
-        return scopes_kwargs
-
     def _prep_wrapped_messages(self, client_info):
         # Precompute the wrapped methods.
         self._wrapped_methods = {
diff --git a/google/cloud/bigquery_connection_v1/services/connection_service/transports/grpc_asyncio.py b/google/cloud/bigquery_connection_v1/services/connection_service/transports/grpc_asyncio.py
index d0e8f8d..23da5e4 100644
--- a/google/cloud/bigquery_connection_v1/services/connection_service/transports/grpc_asyncio.py
+++ b/google/cloud/bigquery_connection_v1/services/connection_service/transports/grpc_asyncio.py
@@ -20,7 +20,6 @@
 from google.api_core import grpc_helpers_async  # type: ignore
 from google.auth import credentials as ga_credentials  # type: ignore
 from google.auth.transport.grpc import SslCredentials  # type: ignore
-import packaging.version
 
 import grpc  # type: ignore
 from grpc.experimental import aio  # type: ignore
diff --git a/google/cloud/bigquery_connection_v1/types/connection.py b/google/cloud/bigquery_connection_v1/types/connection.py
index 92162ee..a03b00b 100644
--- a/google/cloud/bigquery_connection_v1/types/connection.py
+++ b/google/cloud/bigquery_connection_v1/types/connection.py
@@ -148,6 +148,13 @@ class Connection(proto.Message):
     r"""Configuration parameters to establish connection with an
     external data source, except the credential attributes.
 
+    This message has `oneof`_ fields (mutually exclusive fields).
+    For each oneof, at most one member field can be set at the same time.
+    Setting any member of the oneof automatically clears all other
+    members.
+
+    .. _oneof: https://proto-plus-python.readthedocs.io/en/stable/fields.html#oneofs-mutually-exclusive-fields
+
     Attributes:
         name (str):
             The resource name of the connection in the form of:
@@ -159,10 +166,13 @@ class Connection(proto.Message):
             User provided description.
         cloud_sql (google.cloud.bigquery_connection_v1.types.CloudSqlProperties):
             Cloud SQL properties.
+            This field is a member of `oneof`_ ``properties``.
         aws (google.cloud.bigquery_connection_v1.types.AwsProperties):
             Amazon Web Services (AWS) properties.
+            This field is a member of `oneof`_ ``properties``.
         cloud_spanner (google.cloud.bigquery_connection_v1.types.CloudSpannerProperties):
             Cloud Spanner properties.
+            This field is a member of `oneof`_ ``properties``.
         creation_time (int):
             Output only. The creation timestamp of the
             connection.
@@ -251,14 +261,23 @@ class CloudSpannerProperties(proto.Message):
 class AwsProperties(proto.Message):
     r"""Connection properties specific to Amazon Web Services (AWS).
 
+    This message has `oneof`_ fields (mutually exclusive fields).
+    For each oneof, at most one member field can be set at the same time.
+    Setting any member of the oneof automatically clears all other
+    members.
+
+    .. _oneof: https://proto-plus-python.readthedocs.io/en/stable/fields.html#oneofs-mutually-exclusive-fields
+
     Attributes:
         cross_account_role (google.cloud.bigquery_connection_v1.types.AwsCrossAccountRole):
             Authentication using Google owned AWS IAM
             user's access key to assume into customer's AWS
             IAM Role.
+            This field is a member of `oneof`_ ``authentication_method``.
         access_role (google.cloud.bigquery_connection_v1.types.AwsAccessRole):
             Authentication using Google owned service
             account to assume into customer's AWS IAM Role.
+            This field is a member of `oneof`_ ``authentication_method``.
     """
 
     cross_account_role = proto.Field(
diff --git a/noxfile.py b/noxfile.py
index f885c68..2a2001c 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -101,7 +101,7 @@ def default(session):
         "py.test",
         "--quiet",
         f"--junitxml=unit_{session.python}_sponge_log.xml",
-        "--cov=google/cloud",
+        "--cov=google",
         "--cov=tests/unit",
         "--cov-append",
         "--cov-config=.coveragerc",
@@ -175,7 +175,7 @@ def cover(session):
     test runs (not system test runs), and then erases coverage data.
     """
     session.install("coverage", "pytest-cov")
-    session.run("coverage", "report", "--show-missing", "--fail-under=99")
+    session.run("coverage", "report", "--show-missing", "--fail-under=100")
 
     session.run("coverage", "erase")
 
diff --git a/owlbot.py b/owlbot.py
deleted file mode 100644
index d13854b..0000000
--- a/owlbot.py
+++ /dev/null
@@ -1,84 +0,0 @@
-# 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.
-
-"""This script is used to synthesize generated parts of this library."""
-import os
-
-import synthtool as s
-import synthtool.gcp as gcp
-from synthtool.languages import python
-
-common = gcp.CommonTemplates()
-
-default_version = "v1"
-
-for library in s.get_staging_dirs(default_version):
-    s.move(library, excludes=["setup.py", "README.rst", "docs/index.rst", "*.tar.gz"])
-
-s.remove_staging_dirs()
-
-# ----------------------------------------------------------------------------
-# Add templated files
-# ----------------------------------------------------------------------------
-templated_files = common.py_library(cov_level=99, microgenerator=True,)
-python.py_samples(skip_readmes=True)
-s.move(
-    templated_files, excludes=[".coveragerc"]
-)  # the microgenerator has a good coveragerc file
-
-# Remove the replacements below once https://github.com/googleapis/synthtool/pull/1188 is merged
-
-# Update googleapis/repo-automation-bots repo to main in .kokoro/*.sh files
-s.replace(
-    ".kokoro/*.sh", "repo-automation-bots/tree/master", "repo-automation-bots/tree/main"
-)
-
-# Customize CONTRIBUTING.rst to replace master with main
-s.replace(
-    "CONTRIBUTING.rst",
-    "fetch and merge changes from upstream into master",
-    "fetch and merge changes from upstream into main",
-)
-
-s.replace(
-    "CONTRIBUTING.rst", "git merge upstream/master", "git merge upstream/main",
-)
-
-s.replace(
-    "CONTRIBUTING.rst",
-    """export GOOGLE_CLOUD_TESTING_BRANCH=\"master\"""",
-    """export GOOGLE_CLOUD_TESTING_BRANCH=\"main\"""",
-)
-
-s.replace(
-    "CONTRIBUTING.rst", "remote \(``master``\)", "remote (``main``)",
-)
-
-s.replace(
-    "CONTRIBUTING.rst", "blob/master/CONTRIBUTING.rst", "blob/main/CONTRIBUTING.rst",
-)
-
-s.replace(
-    "CONTRIBUTING.rst", "blob/master/noxfile.py", "blob/main/noxfile.py",
-)
-
-s.replace(
-    "docs/conf.py", "master_doc", "root_doc",
-)
-
-s.replace(
-    "docs/conf.py", "# The master toctree document.", "# The root toctree document.",
-)
-
-s.shell.run(["nox", "-s", "blacken"], hide_output=False)
diff --git a/setup.py b/setup.py
index d41dadc..e891c10 100644
--- a/setup.py
+++ b/setup.py
@@ -19,7 +19,7 @@
 import os
 import setuptools  # type: ignore
 
-version = "1.3.0"
+version = "1.3.1"
 
 package_root = os.path.abspath(os.path.dirname(__file__))
 
@@ -47,9 +47,8 @@
         # NOTE: Maintainers, please do not require google-api-core>=2.x.x
         # Until this issue is closed
         # https://github.com/googleapis/google-cloud-python/issues/10566
-        "google-api-core >= 1.22.2, <3.0.0dev",
+        "google-api-core >= 1.28.0, <3.0.0dev",
         "proto-plus >= 1.4.0",
-        "packaging >= 14.3",
         "grpc-google-iam-v1 >= 0.12.3, < 0.13.0dev",
     ),
     python_requires=">=3.6",
@@ -60,6 +59,7 @@
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
         "Topic :: Internet",
         "Topic :: Software Development :: Libraries :: Python Modules",
     ],
diff --git a/testing/constraints-3.6.txt b/testing/constraints-3.6.txt
index fbed252..aaf4a35 100644
--- a/testing/constraints-3.6.txt
+++ b/testing/constraints-3.6.txt
@@ -5,7 +5,6 @@
 #
 # e.g., if setup.py has "foo >= 1.14.0, < 2.0.0dev",
 # Then this file should have foo==1.14.0
-google-api-core==1.26.0
+google-api-core==1.28.0
 proto-plus==1.4.0
 grpc-google-iam-v1==0.12.3
-packaging==14.3
diff --git a/tests/unit/gapic/bigquery_connection_v1/test_connection_service.py b/tests/unit/gapic/bigquery_connection_v1/test_connection_service.py
index 6edc88e..d5a0a83 100644
--- a/tests/unit/gapic/bigquery_connection_v1/test_connection_service.py
+++ b/tests/unit/gapic/bigquery_connection_v1/test_connection_service.py
@@ -15,7 +15,6 @@
 #
 import os
 import mock
-import packaging.version
 
 import grpc
 from grpc.experimental import aio
@@ -40,9 +39,6 @@
 )
 from google.cloud.bigquery_connection_v1.services.connection_service import pagers
 from google.cloud.bigquery_connection_v1.services.connection_service import transports
-from google.cloud.bigquery_connection_v1.services.connection_service.transports.base import (
-    _GOOGLE_AUTH_VERSION,
-)
 from google.cloud.bigquery_connection_v1.types import connection
 from google.cloud.bigquery_connection_v1.types import connection as gcbc_connection
 from google.iam.v1 import iam_policy_pb2  # type: ignore
@@ -54,20 +50,6 @@
 import google.auth
 
 
-# TODO(busunkim): Once google-auth >= 1.25.0 is required transitively
-# through google-api-core:
-# - Delete the auth "less than" test cases
-# - Delete these pytest markers (Make the "greater than or equal to" tests the default).
-requires_google_auth_lt_1_25_0 = pytest.mark.skipif(
-    packaging.version.parse(_GOOGLE_AUTH_VERSION) >= packaging.version.parse("1.25.0"),
-    reason="This test requires google-auth < 1.25.0",
-)
-requires_google_auth_gte_1_25_0 = pytest.mark.skipif(
-    packaging.version.parse(_GOOGLE_AUTH_VERSION) < packaging.version.parse("1.25.0"),
-    reason="This test requires google-auth >= 1.25.0",
-)
-
-
 def client_cert_source_callback():
     return b"cert bytes", b"key bytes"
 
@@ -225,7 +207,7 @@ def test_connection_service_client_client_options(
     options = client_options.ClientOptions(api_endpoint="squid.clam.whelk")
     with mock.patch.object(transport_class, "__init__") as patched:
         patched.return_value = None
-        client = client_class(client_options=options)
+        client = client_class(transport=transport_name, client_options=options)
         patched.assert_called_once_with(
             credentials=None,
             credentials_file=None,
@@ -242,7 +224,7 @@ def test_connection_service_client_client_options(
     with mock.patch.dict(os.environ, {"GOOGLE_API_USE_MTLS_ENDPOINT": "never"}):
         with mock.patch.object(transport_class, "__init__") as patched:
             patched.return_value = None
-            client = client_class()
+            client = client_class(transport=transport_name)
             patched.assert_called_once_with(
                 credentials=None,
                 credentials_file=None,
@@ -259,7 +241,7 @@ def test_connection_service_client_client_options(
     with mock.patch.dict(os.environ, {"GOOGLE_API_USE_MTLS_ENDPOINT": "always"}):
         with mock.patch.object(transport_class, "__init__") as patched:
             patched.return_value = None
-            client = client_class()
+            client = client_class(transport=transport_name)
             patched.assert_called_once_with(
                 credentials=None,
                 credentials_file=None,
@@ -288,7 +270,7 @@ def test_connection_service_client_client_options(
     options = client_options.ClientOptions(quota_project_id="octopus")
     with mock.patch.object(transport_class, "__init__") as patched:
         patched.return_value = None
-        client = client_class(client_options=options)
+        client = client_class(transport=transport_name, client_options=options)
         patched.assert_called_once_with(
             credentials=None,
             credentials_file=None,
@@ -357,7 +339,7 @@ def test_connection_service_client_mtls_env_auto(
         )
         with mock.patch.object(transport_class, "__init__") as patched:
             patched.return_value = None
-            client = client_class(client_options=options)
+            client = client_class(transport=transport_name, client_options=options)
 
             if use_client_cert_env == "false":
                 expected_client_cert_source = None
@@ -399,7 +381,7 @@ def test_connection_service_client_mtls_env_auto(
                         expected_client_cert_source = client_cert_source_callback
 
                     patched.return_value = None
-                    client = client_class()
+                    client = client_class(transport=transport_name)
                     patched.assert_called_once_with(
                         credentials=None,
                         credentials_file=None,
@@ -421,7 +403,7 @@ def test_connection_service_client_mtls_env_auto(
                 return_value=False,
             ):
                 patched.return_value = None
-                client = client_class()
+                client = client_class(transport=transport_name)
                 patched.assert_called_once_with(
                     credentials=None,
                     credentials_file=None,
@@ -452,7 +434,7 @@ def test_connection_service_client_client_options_scopes(
     options = client_options.ClientOptions(scopes=["1", "2"],)
     with mock.patch.object(transport_class, "__init__") as patched:
         patched.return_value = None
-        client = client_class(client_options=options)
+        client = client_class(transport=transport_name, client_options=options)
         patched.assert_called_once_with(
             credentials=None,
             credentials_file=None,
@@ -483,7 +465,7 @@ def test_connection_service_client_client_options_credentials_file(
     options = client_options.ClientOptions(credentials_file="credentials.json")
     with mock.patch.object(transport_class, "__init__") as patched:
         patched.return_value = None
-        client = client_class(client_options=options)
+        client = client_class(transport=transport_name, client_options=options)
         patched.assert_called_once_with(
             credentials=None,
             credentials_file="credentials.json",
@@ -2613,7 +2595,6 @@ def test_connection_service_base_transport():
         transport.close()
 
 
-@requires_google_auth_gte_1_25_0
 def test_connection_service_base_transport_with_credentials_file():
     # Instantiate the base transport with a credentials file
     with mock.patch.object(
@@ -2637,29 +2618,6 @@ def test_connection_service_base_transport_with_credentials_file():
         )
 
 
-@requires_google_auth_lt_1_25_0
-def test_connection_service_base_transport_with_credentials_file_old_google_auth():
-    # Instantiate the base transport with a credentials file
-    with mock.patch.object(
-        google.auth, "load_credentials_from_file", autospec=True
-    ) as load_creds, mock.patch(
-        "google.cloud.bigquery_connection_v1.services.connection_service.transports.ConnectionServiceTransport._prep_wrapped_messages"
-    ) as Transport:
-        Transport.return_value = None
-        load_creds.return_value = (ga_credentials.AnonymousCredentials(), None)
-        transport = transports.ConnectionServiceTransport(
-            credentials_file="credentials.json", quota_project_id="octopus",
-        )
-        load_creds.assert_called_once_with(
-            "credentials.json",
-            scopes=(
-                "https://www.googleapis.com/auth/bigquery",
-                "https://www.googleapis.com/auth/cloud-platform",
-            ),
-            quota_project_id="octopus",
-        )
-
-
 def test_connection_service_base_transport_with_adc():
     # Test the default credentials are used if credentials and credentials_file are None.
     with mock.patch.object(google.auth, "default", autospec=True) as adc, mock.patch(
@@ -2671,7 +2629,6 @@ def test_connection_service_base_transport_with_adc():
         adc.assert_called_once()
 
 
-@requires_google_auth_gte_1_25_0
 def test_connection_service_auth_adc():
     # If no credentials are provided, we should use ADC credentials.
     with mock.patch.object(google.auth, "default", autospec=True) as adc:
@@ -2687,21 +2644,6 @@ def test_connection_service_auth_adc():
         )
 
 
-@requires_google_auth_lt_1_25_0
-def test_connection_service_auth_adc_old_google_auth():
-    # If no credentials are provided, we should use ADC credentials.
-    with mock.patch.object(google.auth, "default", autospec=True) as adc:
-        adc.return_value = (ga_credentials.AnonymousCredentials(), None)
-        ConnectionServiceClient()
-        adc.assert_called_once_with(
-            scopes=(
-                "https://www.googleapis.com/auth/bigquery",
-                "https://www.googleapis.com/auth/cloud-platform",
-            ),
-            quota_project_id=None,
-        )
-
-
 @pytest.mark.parametrize(
     "transport_class",
     [
@@ -2709,7 +2651,6 @@ def test_connection_service_auth_adc_old_google_auth():
         transports.ConnectionServiceGrpcAsyncIOTransport,
     ],
 )
-@requires_google_auth_gte_1_25_0
 def test_connection_service_transport_auth_adc(transport_class):
     # If credentials and host are not provided, the transport class should use
     # ADC credentials.
@@ -2726,29 +2667,6 @@ def test_connection_service_transport_auth_adc(transport_class):
         )
 
 
-@pytest.mark.parametrize(
-    "transport_class",
-    [
-        transports.ConnectionServiceGrpcTransport,
-        transports.ConnectionServiceGrpcAsyncIOTransport,
-    ],
-)
-@requires_google_auth_lt_1_25_0
-def test_connection_service_transport_auth_adc_old_google_auth(transport_class):
-    # If credentials and host are not provided, the transport class should use
-    # ADC credentials.
-    with mock.patch.object(google.auth, "default", autospec=True) as adc:
-        adc.return_value = (ga_credentials.AnonymousCredentials(), None)
-        transport_class(quota_project_id="octopus")
-        adc.assert_called_once_with(
-            scopes=(
-                "https://www.googleapis.com/auth/bigquery",
-                "https://www.googleapis.com/auth/cloud-platform",
-            ),
-            quota_project_id="octopus",
-        )
-
-
 @pytest.mark.parametrize(
     "transport_class,grpc_helpers",
     [