diff --git a/.github/.OwlBot.lock.yaml b/.github/.OwlBot.lock.yaml
index 64f82d6b..757c9dca 100644
--- a/.github/.OwlBot.lock.yaml
+++ b/.github/.OwlBot.lock.yaml
@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:bc5eed3804aec2f05fad42aacf973821d9500c174015341f721a984a0825b6fd
-# created: 2022-04-21T15:43:16.246106921Z
+  digest: sha256:81ed5ecdfc7cac5b699ba4537376f3563f6f04122c4ec9e735d3b3dc1d43dd32
+# created: 2022-05-05T22:08:23.383410683Z
diff --git a/.github/auto-approve.yml b/.github/auto-approve.yml
new file mode 100644
index 00000000..311ebbb8
--- /dev/null
+++ b/.github/auto-approve.yml
@@ -0,0 +1,3 @@
+# https://github.com/googleapis/repo-automation-bots/tree/main/packages/auto-approve
+processes:
+  - "OwlBotTemplateChanges"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e4e3ef3c..b0606274 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,18 @@
 # Changelog
 
-### [1.4.1](https://github.com/googleapis/python-documentai/compare/v1.4.0...v1.4.1) (2022-04-28)
+## [1.4.2](https://github.com/googleapis/python-documentai/compare/v1.4.1...v1.4.2) (2022-06-03)
+
+
+### Bug Fixes
+
+* **deps:** require protobuf <4.0.0dev ([#334](https://github.com/googleapis/python-documentai/issues/334)) ([fbdc01b](https://github.com/googleapis/python-documentai/commit/fbdc01b6670514418e32a90e39540dcb56f53048))
+
+
+### Documentation
+
+* fix changelog header to consistent size ([#333](https://github.com/googleapis/python-documentai/issues/333)) ([bf23383](https://github.com/googleapis/python-documentai/commit/bf23383b869d08bad4a6193e0596ac4e70573539))
+
+## [1.4.1](https://github.com/googleapis/python-documentai/compare/v1.4.0...v1.4.1) (2022-04-28)
 
 
 ### Bug Fixes
@@ -33,7 +45,7 @@
 * remove libcst from setup_requires ([#276](https://github.com/googleapis/python-documentai/issues/276)) ([56c96e4](https://github.com/googleapis/python-documentai/commit/56c96e4cd3427321dac0e8c979aa4e34eefa0b12))
 * resolve DuplicateCredentialArgs error when using credentials_file ([530f2ba](https://github.com/googleapis/python-documentai/commit/530f2ba88cc5abc8f888722246a3610adca001a9))
 
-### [1.2.1](https://github.com/googleapis/python-documentai/compare/v1.2.0...v1.2.1) (2022-01-17)
+## [1.2.1](https://github.com/googleapis/python-documentai/compare/v1.2.0...v1.2.1) (2022-01-17)
 
 
 ### Bug Fixes
diff --git a/samples/snippets/requirements.txt b/samples/snippets/requirements.txt
index b15c1f31..3626cd87 100644
--- a/samples/snippets/requirements.txt
+++ b/samples/snippets/requirements.txt
@@ -1,2 +1,2 @@
-google-cloud-documentai==1.4.0
+google-cloud-documentai==1.4.1
 google-cloud-storage==2.3.0
diff --git a/scripts/readme-gen/readme_gen.py b/scripts/readme-gen/readme_gen.py
index d309d6e9..91b59676 100644
--- a/scripts/readme-gen/readme_gen.py
+++ b/scripts/readme-gen/readme_gen.py
@@ -28,7 +28,10 @@
 jinja_env = jinja2.Environment(
     trim_blocks=True,
     loader=jinja2.FileSystemLoader(
-        os.path.abspath(os.path.join(os.path.dirname(__file__), 'templates'))))
+        os.path.abspath(os.path.join(os.path.dirname(__file__), "templates"))
+    ),
+    autoescape=True,
+)
 
 README_TMPL = jinja_env.get_template('README.tmpl.rst')
 
diff --git a/setup.py b/setup.py
index 6392f42e..826c33e0 100644
--- a/setup.py
+++ b/setup.py
@@ -20,7 +20,7 @@
 
 import setuptools  # type: ignore
 
-version = "1.4.1"
+version = "1.4.2"
 
 package_root = os.path.abspath(os.path.dirname(__file__))
 
@@ -50,7 +50,8 @@
         # Until this issue is closed
         # https://github.com/googleapis/google-cloud-python/issues/10566
         "google-api-core[grpc] >= 1.31.5, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.0",
-        "proto-plus >= 1.15.0",
+        "proto-plus >= 1.15.0, <2.0.0dev",
+        "protobuf >= 3.19.0, <4.0.0dev",
     ),
     python_requires=">=3.6",
     classifiers=[
diff --git a/testing/constraints-3.6.txt b/testing/constraints-3.6.txt
index b666ca6c..ec8ca201 100644
--- a/testing/constraints-3.6.txt
+++ b/testing/constraints-3.6.txt
@@ -7,3 +7,4 @@
 # Then this file should have foo==1.14.0
 google-api-core==1.31.5
 proto-plus==1.15.0
+protobuf==3.19.0
diff --git a/testing/constraints-3.7.txt b/testing/constraints-3.7.txt
index e69de29b..ec8ca201 100644
--- a/testing/constraints-3.7.txt
+++ b/testing/constraints-3.7.txt
@@ -0,0 +1,10 @@
+# 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-api-core==1.31.5
+proto-plus==1.15.0
+protobuf==3.19.0
diff --git a/tests/unit/gapic/documentai_v1/test_document_processor_service.py b/tests/unit/gapic/documentai_v1/test_document_processor_service.py
index 82d570f2..2faff032 100644
--- a/tests/unit/gapic/documentai_v1/test_document_processor_service.py
+++ b/tests/unit/gapic/documentai_v1/test_document_processor_service.py
@@ -13,9 +13,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-import math
 import os
 
+# try/except added for compatibility with python < 3.8
+try:
+    from unittest import mock
+    from unittest.mock import AsyncMock
+except ImportError:
+    import mock
+
+import math
+
 from google.api_core import (
     future,
     gapic_v1,
@@ -45,7 +53,6 @@
 from google.type import postal_address_pb2  # type: ignore
 import grpc
 from grpc.experimental import aio
-import mock
 from proto.marshal.rules.dates import DurationRule, TimestampRule
 import pytest
 
diff --git a/tests/unit/gapic/documentai_v1beta2/test_document_understanding_service.py b/tests/unit/gapic/documentai_v1beta2/test_document_understanding_service.py
index 3acba2d8..93f3f1fa 100644
--- a/tests/unit/gapic/documentai_v1beta2/test_document_understanding_service.py
+++ b/tests/unit/gapic/documentai_v1beta2/test_document_understanding_service.py
@@ -13,9 +13,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-import math
 import os
 
+# try/except added for compatibility with python < 3.8
+try:
+    from unittest import mock
+    from unittest.mock import AsyncMock
+except ImportError:
+    import mock
+
+import math
+
 from google.api_core import (
     future,
     gapic_v1,
@@ -36,7 +44,6 @@
 from google.rpc import status_pb2  # type: ignore
 import grpc
 from grpc.experimental import aio
-import mock
 from proto.marshal.rules.dates import DurationRule, TimestampRule
 import pytest
 
diff --git a/tests/unit/gapic/documentai_v1beta3/test_document_processor_service.py b/tests/unit/gapic/documentai_v1beta3/test_document_processor_service.py
index 458fc7a9..91610b6d 100644
--- a/tests/unit/gapic/documentai_v1beta3/test_document_processor_service.py
+++ b/tests/unit/gapic/documentai_v1beta3/test_document_processor_service.py
@@ -13,9 +13,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-import math
 import os
 
+# try/except added for compatibility with python < 3.8
+try:
+    from unittest import mock
+    from unittest.mock import AsyncMock
+except ImportError:
+    import mock
+
+import math
+
 from google.api_core import (
     future,
     gapic_v1,
@@ -45,7 +53,6 @@
 from google.type import postal_address_pb2  # type: ignore
 import grpc
 from grpc.experimental import aio
-import mock
 from proto.marshal.rules.dates import DurationRule, TimestampRule
 import pytest