diff --git a/.librarian/state.yaml b/.librarian/state.yaml
index 121583a2d..f1c099fac 100644
--- a/.librarian/state.yaml
+++ b/.librarian/state.yaml
@@ -1,4 +1,4 @@
-image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:b8058df4c45e9a6e07f6b4d65b458d0d059241dd34c814f151c8bf6b89211209
+image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:a38add811f7f139d6a385b22d283ad09ef305b8cf50382ef62f0ce690787f021
 libraries:
   - id: google-cloud-firestore
     version: 2.23.0
diff --git a/google/cloud/firestore_admin_v1/services/firestore_admin/async_client.py b/google/cloud/firestore_admin_v1/services/firestore_admin/async_client.py
index a2800e34e..7c4ee7b53 100644
--- a/google/cloud/firestore_admin_v1/services/firestore_admin/async_client.py
+++ b/google/cloud/firestore_admin_v1/services/firestore_admin/async_client.py
@@ -45,8 +45,6 @@
 except AttributeError:  # pragma: NO COVER
     OptionalRetry = Union[retries.AsyncRetry, object, None]  # type: ignore
 
-from google.api_core import operation as gac_operation  # type: ignore
-from google.api_core import operation_async  # type: ignore
 from google.cloud.firestore_admin_v1.services.firestore_admin import pagers
 from google.cloud.firestore_admin_v1.types import backup
 from google.cloud.firestore_admin_v1.types import database
@@ -62,10 +60,12 @@
 from google.cloud.firestore_admin_v1.types import user_creds as gfa_user_creds
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import duration_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
-from google.protobuf import field_mask_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.api_core.operation as gac_operation  # type: ignore
+import google.api_core.operation_async as operation_async  # type: ignore
+import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
+import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 from .transports.base import FirestoreAdminTransport, DEFAULT_CLIENT_INFO
 from .transports.grpc_asyncio import FirestoreAdminGrpcAsyncIOTransport
 from .client import FirestoreAdminClient
@@ -183,7 +183,10 @@ def from_service_account_info(cls, info: dict, *args, **kwargs):
         Returns:
             FirestoreAdminAsyncClient: The constructed client.
         """
-        return FirestoreAdminClient.from_service_account_info.__func__(FirestoreAdminAsyncClient, info, *args, **kwargs)  # type: ignore
+        sa_info_func = (
+            FirestoreAdminClient.from_service_account_info.__func__  # type: ignore
+        )
+        return sa_info_func(FirestoreAdminAsyncClient, info, *args, **kwargs)
 
     @classmethod
     def from_service_account_file(cls, filename: str, *args, **kwargs):
@@ -199,7 +202,10 @@ def from_service_account_file(cls, filename: str, *args, **kwargs):
         Returns:
             FirestoreAdminAsyncClient: The constructed client.
         """
-        return FirestoreAdminClient.from_service_account_file.__func__(FirestoreAdminAsyncClient, filename, *args, **kwargs)  # type: ignore
+        sa_file_func = (
+            FirestoreAdminClient.from_service_account_file.__func__  # type: ignore
+        )
+        return sa_file_func(FirestoreAdminAsyncClient, filename, *args, **kwargs)
 
     from_service_account_json = from_service_account_file
 
diff --git a/google/cloud/firestore_admin_v1/services/firestore_admin/client.py b/google/cloud/firestore_admin_v1/services/firestore_admin/client.py
index b55c157cf..8804083c0 100644
--- a/google/cloud/firestore_admin_v1/services/firestore_admin/client.py
+++ b/google/cloud/firestore_admin_v1/services/firestore_admin/client.py
@@ -61,8 +61,6 @@
 
 _LOGGER = std_logging.getLogger(__name__)
 
-from google.api_core import operation as gac_operation  # type: ignore
-from google.api_core import operation_async  # type: ignore
 from google.cloud.firestore_admin_v1.services.firestore_admin import pagers
 from google.cloud.firestore_admin_v1.types import backup
 from google.cloud.firestore_admin_v1.types import database
@@ -78,10 +76,12 @@
 from google.cloud.firestore_admin_v1.types import user_creds as gfa_user_creds
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import duration_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
-from google.protobuf import field_mask_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.api_core.operation as gac_operation  # type: ignore
+import google.api_core.operation_async as operation_async  # type: ignore
+import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
+import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 from .transports.base import FirestoreAdminTransport, DEFAULT_CLIENT_INFO
 from .transports.grpc import FirestoreAdminGrpcTransport
 from .transports.grpc_asyncio import FirestoreAdminGrpcAsyncIOTransport
diff --git a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/base.py b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/base.py
index 7d582d9b5..995f01381 100644
--- a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/base.py
+++ b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/base.py
@@ -38,7 +38,7 @@
 from google.cloud.firestore_admin_v1.types import user_creds as gfa_user_creds
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 
 DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
     gapic_version=package_version.__version__
@@ -97,8 +97,6 @@ def __init__(
                 be used for service account credentials.
         """
 
-        scopes_kwargs = {"scopes": scopes, "default_scopes": self.AUTH_SCOPES}
-
         # Save the scopes.
         self._scopes = scopes
         if not hasattr(self, "_ignore_credentials"):
@@ -113,11 +111,16 @@ def __init__(
 
         if credentials_file is not None:
             credentials, _ = google.auth.load_credentials_from_file(
-                credentials_file, **scopes_kwargs, quota_project_id=quota_project_id
+                credentials_file,
+                scopes=scopes,
+                quota_project_id=quota_project_id,
+                default_scopes=self.AUTH_SCOPES,
             )
         elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(
-                **scopes_kwargs, quota_project_id=quota_project_id
+                scopes=scopes,
+                quota_project_id=quota_project_id,
+                default_scopes=self.AUTH_SCOPES,
             )
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/grpc.py b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/grpc.py
index f6531a190..1630b3599 100644
--- a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/grpc.py
+++ b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/grpc.py
@@ -41,7 +41,7 @@
 from google.cloud.firestore_admin_v1.types import user_creds as gfa_user_creds
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 from .base import FirestoreAdminTransport, DEFAULT_CLIENT_INFO
 
 try:
diff --git a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/grpc_asyncio.py b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/grpc_asyncio.py
index 117707853..e80be1c43 100644
--- a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/grpc_asyncio.py
+++ b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/grpc_asyncio.py
@@ -44,7 +44,7 @@
 from google.cloud.firestore_admin_v1.types import user_creds as gfa_user_creds
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 from .base import FirestoreAdminTransport, DEFAULT_CLIENT_INFO
 from .grpc import FirestoreAdminGrpcTransport
 
diff --git a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/rest.py b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/rest.py
index 41e819c87..69dacd798 100644
--- a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/rest.py
+++ b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/rest.py
@@ -43,7 +43,7 @@
 from google.cloud.firestore_admin_v1.types import schedule
 from google.cloud.firestore_admin_v1.types import user_creds
 from google.cloud.firestore_admin_v1.types import user_creds as gfa_user_creds
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
 
 
@@ -2105,7 +2105,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -2257,7 +2257,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -2569,7 +2569,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -2721,7 +2721,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -3014,7 +3014,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -3124,7 +3124,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -3238,7 +3238,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -3377,7 +3377,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -3486,7 +3486,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -3913,7 +3913,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -4970,7 +4970,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -6175,7 +6175,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -6487,7 +6487,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -6639,7 +6639,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
diff --git a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/rest_base.py b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/rest_base.py
index 56b6ce93f..ec1774ff2 100644
--- a/google/cloud/firestore_admin_v1/services/firestore_admin/transports/rest_base.py
+++ b/google/cloud/firestore_admin_v1/services/firestore_admin/transports/rest_base.py
@@ -33,7 +33,7 @@
 from google.cloud.firestore_admin_v1.types import schedule
 from google.cloud.firestore_admin_v1.types import user_creds
 from google.cloud.firestore_admin_v1.types import user_creds as gfa_user_creds
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
 
 
diff --git a/google/cloud/firestore_admin_v1/types/backup.py b/google/cloud/firestore_admin_v1/types/backup.py
index 02c594a22..4c325630f 100644
--- a/google/cloud/firestore_admin_v1/types/backup.py
+++ b/google/cloud/firestore_admin_v1/types/backup.py
@@ -19,7 +19,7 @@
 
 import proto  # type: ignore
 
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_admin_v1/types/database.py b/google/cloud/firestore_admin_v1/types/database.py
index f46bede62..93cee1d38 100644
--- a/google/cloud/firestore_admin_v1/types/database.py
+++ b/google/cloud/firestore_admin_v1/types/database.py
@@ -19,8 +19,8 @@
 
 import proto  # type: ignore
 
-from google.protobuf import duration_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_admin_v1/types/firestore_admin.py b/google/cloud/firestore_admin_v1/types/firestore_admin.py
index 9ede35cac..21b9502ba 100644
--- a/google/cloud/firestore_admin_v1/types/firestore_admin.py
+++ b/google/cloud/firestore_admin_v1/types/firestore_admin.py
@@ -26,8 +26,8 @@
 from google.cloud.firestore_admin_v1.types import schedule
 from google.cloud.firestore_admin_v1.types import snapshot
 from google.cloud.firestore_admin_v1.types import user_creds as gfa_user_creds
-from google.protobuf import field_mask_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_admin_v1/types/operation.py b/google/cloud/firestore_admin_v1/types/operation.py
index c50455693..7ae83dc03 100644
--- a/google/cloud/firestore_admin_v1/types/operation.py
+++ b/google/cloud/firestore_admin_v1/types/operation.py
@@ -21,7 +21,7 @@
 
 from google.cloud.firestore_admin_v1.types import index as gfa_index
 from google.cloud.firestore_admin_v1.types import snapshot
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_admin_v1/types/schedule.py b/google/cloud/firestore_admin_v1/types/schedule.py
index a767edfe1..879124fc2 100644
--- a/google/cloud/firestore_admin_v1/types/schedule.py
+++ b/google/cloud/firestore_admin_v1/types/schedule.py
@@ -19,9 +19,9 @@
 
 import proto  # type: ignore
 
-from google.protobuf import duration_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
-from google.type import dayofweek_pb2  # type: ignore
+import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
+import google.type.dayofweek_pb2 as dayofweek_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_admin_v1/types/snapshot.py b/google/cloud/firestore_admin_v1/types/snapshot.py
index e56a125f5..e3352d4cf 100644
--- a/google/cloud/firestore_admin_v1/types/snapshot.py
+++ b/google/cloud/firestore_admin_v1/types/snapshot.py
@@ -19,7 +19,7 @@
 
 import proto  # type: ignore
 
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_admin_v1/types/user_creds.py b/google/cloud/firestore_admin_v1/types/user_creds.py
index 39bd11947..956dc28f2 100644
--- a/google/cloud/firestore_admin_v1/types/user_creds.py
+++ b/google/cloud/firestore_admin_v1/types/user_creds.py
@@ -19,7 +19,7 @@
 
 import proto  # type: ignore
 
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_bundle/types/bundle.py b/google/cloud/firestore_bundle/types/bundle.py
index 3671833d9..6714155ed 100644
--- a/google/cloud/firestore_bundle/types/bundle.py
+++ b/google/cloud/firestore_bundle/types/bundle.py
@@ -19,9 +19,9 @@
 
 import proto  # type: ignore
 
-from google.cloud.firestore_v1.types import document as document_pb2  # type: ignore
-from google.cloud.firestore_v1.types import query as query_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.firestore.v1.document_pb2 as document_pb2  # type: ignore
+import google.firestore.v1.query_pb2 as query_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_v1/services/firestore/async_client.py b/google/cloud/firestore_v1/services/firestore/async_client.py
index 3557eb94c..d99e85beb 100644
--- a/google/cloud/firestore_v1/services/firestore/async_client.py
+++ b/google/cloud/firestore_v1/services/firestore/async_client.py
@@ -60,8 +60,8 @@
 from google.cloud.firestore_v1.types import write as gf_write
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
-from google.rpc import status_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
+import google.rpc.status_pb2 as status_pb2  # type: ignore
 from .transports.base import FirestoreTransport, DEFAULT_CLIENT_INFO
 from .transports.grpc_asyncio import FirestoreGrpcAsyncIOTransport
 from .client import FirestoreClient
@@ -129,7 +129,10 @@ def from_service_account_info(cls, info: dict, *args, **kwargs):
         Returns:
             FirestoreAsyncClient: The constructed client.
         """
-        return FirestoreClient.from_service_account_info.__func__(FirestoreAsyncClient, info, *args, **kwargs)  # type: ignore
+        sa_info_func = (
+            FirestoreClient.from_service_account_info.__func__  # type: ignore
+        )
+        return sa_info_func(FirestoreAsyncClient, info, *args, **kwargs)
 
     @classmethod
     def from_service_account_file(cls, filename: str, *args, **kwargs):
@@ -145,7 +148,10 @@ def from_service_account_file(cls, filename: str, *args, **kwargs):
         Returns:
             FirestoreAsyncClient: The constructed client.
         """
-        return FirestoreClient.from_service_account_file.__func__(FirestoreAsyncClient, filename, *args, **kwargs)  # type: ignore
+        sa_file_func = (
+            FirestoreClient.from_service_account_file.__func__  # type: ignore
+        )
+        return sa_file_func(FirestoreAsyncClient, filename, *args, **kwargs)
 
     from_service_account_json = from_service_account_file
 
diff --git a/google/cloud/firestore_v1/services/firestore/client.py b/google/cloud/firestore_v1/services/firestore/client.py
index ac86aaa9e..6a6b284f5 100644
--- a/google/cloud/firestore_v1/services/firestore/client.py
+++ b/google/cloud/firestore_v1/services/firestore/client.py
@@ -75,8 +75,8 @@
 from google.cloud.firestore_v1.types import write as gf_write
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
-from google.rpc import status_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
+import google.rpc.status_pb2 as status_pb2  # type: ignore
 from .transports.base import FirestoreTransport, DEFAULT_CLIENT_INFO
 from .transports.grpc import FirestoreGrpcTransport
 from .transports.grpc_asyncio import FirestoreGrpcAsyncIOTransport
diff --git a/google/cloud/firestore_v1/services/firestore/transports/base.py b/google/cloud/firestore_v1/services/firestore/transports/base.py
index 905dded09..d0fbea9c2 100644
--- a/google/cloud/firestore_v1/services/firestore/transports/base.py
+++ b/google/cloud/firestore_v1/services/firestore/transports/base.py
@@ -32,7 +32,7 @@
 from google.cloud.firestore_v1.types import firestore
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 
 DEFAULT_CLIENT_INFO = gapic_v1.client_info.ClientInfo(
     gapic_version=package_version.__version__
@@ -91,8 +91,6 @@ def __init__(
                 be used for service account credentials.
         """
 
-        scopes_kwargs = {"scopes": scopes, "default_scopes": self.AUTH_SCOPES}
-
         # Save the scopes.
         self._scopes = scopes
         if not hasattr(self, "_ignore_credentials"):
@@ -107,11 +105,16 @@ def __init__(
 
         if credentials_file is not None:
             credentials, _ = google.auth.load_credentials_from_file(
-                credentials_file, **scopes_kwargs, quota_project_id=quota_project_id
+                credentials_file,
+                scopes=scopes,
+                quota_project_id=quota_project_id,
+                default_scopes=self.AUTH_SCOPES,
             )
         elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(
-                **scopes_kwargs, quota_project_id=quota_project_id
+                scopes=scopes,
+                quota_project_id=quota_project_id,
+                default_scopes=self.AUTH_SCOPES,
             )
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/google/cloud/firestore_v1/services/firestore/transports/grpc.py b/google/cloud/firestore_v1/services/firestore/transports/grpc.py
index f057d16e3..4e8f238f0 100644
--- a/google/cloud/firestore_v1/services/firestore/transports/grpc.py
+++ b/google/cloud/firestore_v1/services/firestore/transports/grpc.py
@@ -35,7 +35,7 @@
 from google.cloud.firestore_v1.types import firestore
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 from .base import FirestoreTransport, DEFAULT_CLIENT_INFO
 
 try:
diff --git a/google/cloud/firestore_v1/services/firestore/transports/grpc_asyncio.py b/google/cloud/firestore_v1/services/firestore/transports/grpc_asyncio.py
index cf6006672..031748e51 100644
--- a/google/cloud/firestore_v1/services/firestore/transports/grpc_asyncio.py
+++ b/google/cloud/firestore_v1/services/firestore/transports/grpc_asyncio.py
@@ -38,7 +38,7 @@
 from google.cloud.firestore_v1.types import firestore
 from google.cloud.location import locations_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 from .base import FirestoreTransport, DEFAULT_CLIENT_INFO
 from .grpc import FirestoreGrpcTransport
 
diff --git a/google/cloud/firestore_v1/services/firestore/transports/rest.py b/google/cloud/firestore_v1/services/firestore/transports/rest.py
index 845569d97..7a0fac8dd 100644
--- a/google/cloud/firestore_v1/services/firestore/transports/rest.py
+++ b/google/cloud/firestore_v1/services/firestore/transports/rest.py
@@ -37,7 +37,7 @@
 from google.cloud.firestore_v1.types import document
 from google.cloud.firestore_v1.types import document as gf_document
 from google.cloud.firestore_v1.types import firestore
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
 
 
@@ -1897,7 +1897,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
@@ -2796,7 +2796,7 @@ def __call__(
                 )
                 method = transcoded_request["method"]
                 try:
-                    request_payload = json_format.MessageToJson(request)
+                    request_payload = type(request).to_json(request)
                 except:
                     request_payload = None
                 http_request = {
diff --git a/google/cloud/firestore_v1/services/firestore/transports/rest_base.py b/google/cloud/firestore_v1/services/firestore/transports/rest_base.py
index 80ce35e49..f0efd4ac7 100644
--- a/google/cloud/firestore_v1/services/firestore/transports/rest_base.py
+++ b/google/cloud/firestore_v1/services/firestore/transports/rest_base.py
@@ -28,7 +28,7 @@
 from google.cloud.firestore_v1.types import document
 from google.cloud.firestore_v1.types import document as gf_document
 from google.cloud.firestore_v1.types import firestore
-from google.protobuf import empty_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
 from google.longrunning import operations_pb2  # type: ignore
 
 
diff --git a/google/cloud/firestore_v1/types/common.py b/google/cloud/firestore_v1/types/common.py
index 01fb3d263..2d6552104 100644
--- a/google/cloud/firestore_v1/types/common.py
+++ b/google/cloud/firestore_v1/types/common.py
@@ -19,7 +19,7 @@
 
 import proto  # type: ignore
 
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_v1/types/document.py b/google/cloud/firestore_v1/types/document.py
index 8073ad97a..2a85e3ce6 100644
--- a/google/cloud/firestore_v1/types/document.py
+++ b/google/cloud/firestore_v1/types/document.py
@@ -19,9 +19,9 @@
 
 import proto  # type: ignore
 
-from google.protobuf import struct_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
-from google.type import latlng_pb2  # type: ignore
+import google.protobuf.struct_pb2 as struct_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
+import google.type.latlng_pb2 as latlng_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_v1/types/explain_stats.py b/google/cloud/firestore_v1/types/explain_stats.py
index b0f9421ba..fa8508021 100644
--- a/google/cloud/firestore_v1/types/explain_stats.py
+++ b/google/cloud/firestore_v1/types/explain_stats.py
@@ -19,7 +19,7 @@
 
 import proto  # type: ignore
 
-from google.protobuf import any_pb2  # type: ignore
+import google.protobuf.any_pb2 as any_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_v1/types/firestore.py b/google/cloud/firestore_v1/types/firestore.py
index 4e53ba313..d2df9a1e9 100644
--- a/google/cloud/firestore_v1/types/firestore.py
+++ b/google/cloud/firestore_v1/types/firestore.py
@@ -27,9 +27,9 @@
 from google.cloud.firestore_v1.types import query as gf_query
 from google.cloud.firestore_v1.types import query_profile
 from google.cloud.firestore_v1.types import write
-from google.protobuf import timestamp_pb2  # type: ignore
-from google.protobuf import wrappers_pb2  # type: ignore
-from google.rpc import status_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
+import google.protobuf.wrappers_pb2 as wrappers_pb2  # type: ignore
+import google.rpc.status_pb2 as status_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_v1/types/query.py b/google/cloud/firestore_v1/types/query.py
index d50742785..12777de78 100644
--- a/google/cloud/firestore_v1/types/query.py
+++ b/google/cloud/firestore_v1/types/query.py
@@ -20,7 +20,7 @@
 import proto  # type: ignore
 
 from google.cloud.firestore_v1.types import document
-from google.protobuf import wrappers_pb2  # type: ignore
+import google.protobuf.wrappers_pb2 as wrappers_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_v1/types/query_profile.py b/google/cloud/firestore_v1/types/query_profile.py
index f93184ae3..c15b70c1e 100644
--- a/google/cloud/firestore_v1/types/query_profile.py
+++ b/google/cloud/firestore_v1/types/query_profile.py
@@ -19,8 +19,8 @@
 
 import proto  # type: ignore
 
-from google.protobuf import duration_pb2  # type: ignore
-from google.protobuf import struct_pb2  # type: ignore
+import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
+import google.protobuf.struct_pb2 as struct_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/google/cloud/firestore_v1/types/write.py b/google/cloud/firestore_v1/types/write.py
index e393b9148..f0c51ebe7 100644
--- a/google/cloud/firestore_v1/types/write.py
+++ b/google/cloud/firestore_v1/types/write.py
@@ -22,7 +22,7 @@
 from google.cloud.firestore_v1.types import bloom_filter
 from google.cloud.firestore_v1.types import common
 from google.cloud.firestore_v1.types import document as gf_document
-from google.protobuf import timestamp_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
 
 
 __protobuf__ = proto.module(
diff --git a/noxfile.py b/noxfile.py
index ae348040f..3e8b80770 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -75,7 +75,6 @@
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = [
     "pytest-asyncio==0.21.2",
     "six",
-    "pyyaml",
 ]
 SYSTEM_TEST_LOCAL_DEPENDENCIES: List[str] = []
 SYSTEM_TEST_DEPENDENCIES: List[str] = []
@@ -85,6 +84,7 @@
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 
 nox.options.sessions = [
+    "unit-3.9",
     "unit-3.10",
     "unit-3.11",
     "unit-3.12",
diff --git a/tests/unit/gapic/firestore_admin_v1/test_firestore_admin.py b/tests/unit/gapic/firestore_admin_v1/test_firestore_admin.py
index 7ef138d15..63a4eaf48 100644
--- a/tests/unit/gapic/firestore_admin_v1/test_firestore_admin.py
+++ b/tests/unit/gapic/firestore_admin_v1/test_firestore_admin.py
@@ -29,6 +29,7 @@
 import json
 import math
 import pytest
+from collections.abc import Sequence, Mapping
 from google.api_core import api_core_version
 from proto.marshal.rules.dates import DurationRule, TimestampRule
 from proto.marshal.rules import wrappers
@@ -51,7 +52,6 @@
 from google.api_core import grpc_helpers
 from google.api_core import grpc_helpers_async
 from google.api_core import operation
-from google.api_core import operation_async  # type: ignore
 from google.api_core import operations_v1
 from google.api_core import path_template
 from google.api_core import retry as retries
@@ -81,12 +81,13 @@
 from google.cloud.location import locations_pb2
 from google.longrunning import operations_pb2  # type: ignore
 from google.oauth2 import service_account
-from google.protobuf import duration_pb2  # type: ignore
-from google.protobuf import empty_pb2  # type: ignore
-from google.protobuf import field_mask_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
-from google.type import dayofweek_pb2  # type: ignore
+import google.api_core.operation_async as operation_async  # type: ignore
 import google.auth
+import google.protobuf.duration_pb2 as duration_pb2  # type: ignore
+import google.protobuf.empty_pb2 as empty_pb2  # type: ignore
+import google.protobuf.field_mask_pb2 as field_mask_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
+import google.type.dayofweek_pb2 as dayofweek_pb2  # type: ignore
 
 
 CRED_INFO_JSON = {
diff --git a/tests/unit/gapic/firestore_v1/test_firestore.py b/tests/unit/gapic/firestore_v1/test_firestore.py
index e3821e772..f9af1df6b 100644
--- a/tests/unit/gapic/firestore_v1/test_firestore.py
+++ b/tests/unit/gapic/firestore_v1/test_firestore.py
@@ -29,6 +29,7 @@
 import json
 import math
 import pytest
+from collections.abc import Sequence, Mapping
 from google.api_core import api_core_version
 from proto.marshal.rules.dates import DurationRule, TimestampRule
 from proto.marshal.rules import wrappers
@@ -70,12 +71,12 @@
 from google.cloud.location import locations_pb2
 from google.longrunning import operations_pb2  # type: ignore
 from google.oauth2 import service_account
-from google.protobuf import struct_pb2  # type: ignore
-from google.protobuf import timestamp_pb2  # type: ignore
-from google.protobuf import wrappers_pb2  # type: ignore
-from google.rpc import status_pb2  # type: ignore
-from google.type import latlng_pb2  # type: ignore
 import google.auth
+import google.protobuf.struct_pb2 as struct_pb2  # type: ignore
+import google.protobuf.timestamp_pb2 as timestamp_pb2  # type: ignore
+import google.protobuf.wrappers_pb2 as wrappers_pb2  # type: ignore
+import google.rpc.status_pb2 as status_pb2  # type: ignore
+import google.type.latlng_pb2 as latlng_pb2  # type: ignore
 
 
 CRED_INFO_JSON = {