diff --git a/.github/.OwlBot.lock.yaml b/.github/.OwlBot.lock.yaml
index 58fcbee..c701359 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:c8878270182edaab99f2927969d4f700c3af265accd472c3425deedff2b7fd93
-# created: 2022-07-14T01:58:16.015625351Z
+  digest: sha256:c6c965a4bf40c19011b11f87dbc801a66d3a23fbc6704102be064ef31c51f1c3
+# created: 2022-08-09T15:58:56.463048506Z
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index b46d730..7092a13 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -10,7 +10,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Setup Python
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
       with:
         python-version: "3.10"
     - name: Install nox
@@ -26,7 +26,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Setup Python
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
       with:
         python-version: "3.10"
     - name: Install nox
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index f512a49..d2aee5b 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -10,7 +10,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Setup Python
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
       with:
         python-version: "3.10"
     - name: Install nox
diff --git a/.github/workflows/unittest.yml b/.github/workflows/unittest.yml
index 5531b01..87ade4d 100644
--- a/.github/workflows/unittest.yml
+++ b/.github/workflows/unittest.yml
@@ -13,7 +13,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Setup Python
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python }}
     - name: Install nox
@@ -39,7 +39,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v3
     - name: Setup Python
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@v4
       with:
         python-version: "3.10"
     - name: Install coverage
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 40f4fba..c90ceec 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## [1.5.1](https://github.com/googleapis/python-appengine-admin/compare/v1.5.0...v1.5.1) (2022-08-11)
+
+
+### Bug Fixes
+
+* **deps:** allow protobuf < 5.0.0 ([#184](https://github.com/googleapis/python-appengine-admin/issues/184)) ([ee28547](https://github.com/googleapis/python-appengine-admin/commit/ee28547fb402ae8917a70ad776fa99e927599852))
+* **deps:** require proto-plus >= 1.22.0 ([ee28547](https://github.com/googleapis/python-appengine-admin/commit/ee28547fb402ae8917a70ad776fa99e927599852))
+
 ## [1.5.0](https://github.com/googleapis/python-appengine-admin/compare/v1.4.1...v1.5.0) (2022-07-18)
 
 
diff --git a/google/cloud/appengine_admin_v1/services/domain_mappings/async_client.py b/google/cloud/appengine_admin_v1/services/domain_mappings/async_client.py
index 69c656a..f0eae80 100644
--- a/google/cloud/appengine_admin_v1/services/domain_mappings/async_client.py
+++ b/google/cloud/appengine_admin_v1/services/domain_mappings/async_client.py
@@ -601,9 +601,6 @@ async def sample_delete_domain_mapping():
 
                       }
 
-                   The JSON representation for Empty is empty JSON
-                   object {}.
-
         """
         # Create or coerce a protobuf request object.
         request = appengine.DeleteDomainMappingRequest(request)
diff --git a/google/cloud/appengine_admin_v1/services/domain_mappings/client.py b/google/cloud/appengine_admin_v1/services/domain_mappings/client.py
index cca07c4..5eb702a 100644
--- a/google/cloud/appengine_admin_v1/services/domain_mappings/client.py
+++ b/google/cloud/appengine_admin_v1/services/domain_mappings/client.py
@@ -810,9 +810,6 @@ def sample_delete_domain_mapping():
 
                       }
 
-                   The JSON representation for Empty is empty JSON
-                   object {}.
-
         """
         # Create or coerce a protobuf request object.
         # Minor optimization to avoid making a copy if the user passes
diff --git a/google/cloud/appengine_admin_v1/services/instances/async_client.py b/google/cloud/appengine_admin_v1/services/instances/async_client.py
index 7ac7e95..960a309 100644
--- a/google/cloud/appengine_admin_v1/services/instances/async_client.py
+++ b/google/cloud/appengine_admin_v1/services/instances/async_client.py
@@ -434,9 +434,6 @@ async def sample_delete_instance():
 
                       }
 
-                   The JSON representation for Empty is empty JSON
-                   object {}.
-
         """
         # Create or coerce a protobuf request object.
         request = appengine.DeleteInstanceRequest(request)
diff --git a/google/cloud/appengine_admin_v1/services/instances/client.py b/google/cloud/appengine_admin_v1/services/instances/client.py
index 8a8d3f5..5cd1b2b 100644
--- a/google/cloud/appengine_admin_v1/services/instances/client.py
+++ b/google/cloud/appengine_admin_v1/services/instances/client.py
@@ -667,9 +667,6 @@ def sample_delete_instance():
 
                       }
 
-                   The JSON representation for Empty is empty JSON
-                   object {}.
-
         """
         # Create or coerce a protobuf request object.
         # Minor optimization to avoid making a copy if the user passes
diff --git a/google/cloud/appengine_admin_v1/services/services/async_client.py b/google/cloud/appengine_admin_v1/services/services/async_client.py
index 1e28bde..fdc288c 100644
--- a/google/cloud/appengine_admin_v1/services/services/async_client.py
+++ b/google/cloud/appengine_admin_v1/services/services/async_client.py
@@ -516,9 +516,6 @@ async def sample_delete_service():
 
                       }
 
-                   The JSON representation for Empty is empty JSON
-                   object {}.
-
         """
         # Create or coerce a protobuf request object.
         request = appengine.DeleteServiceRequest(request)
diff --git a/google/cloud/appengine_admin_v1/services/services/client.py b/google/cloud/appengine_admin_v1/services/services/client.py
index 603a883..09508c4 100644
--- a/google/cloud/appengine_admin_v1/services/services/client.py
+++ b/google/cloud/appengine_admin_v1/services/services/client.py
@@ -730,9 +730,6 @@ def sample_delete_service():
 
                       }
 
-                   The JSON representation for Empty is empty JSON
-                   object {}.
-
         """
         # Create or coerce a protobuf request object.
         # Minor optimization to avoid making a copy if the user passes
diff --git a/google/cloud/appengine_admin_v1/services/versions/async_client.py b/google/cloud/appengine_admin_v1/services/versions/async_client.py
index 1ed6d88..6a60290 100644
--- a/google/cloud/appengine_admin_v1/services/versions/async_client.py
+++ b/google/cloud/appengine_admin_v1/services/versions/async_client.py
@@ -624,9 +624,6 @@ async def sample_delete_version():
 
                       }
 
-                   The JSON representation for Empty is empty JSON
-                   object {}.
-
         """
         # Create or coerce a protobuf request object.
         request = appengine.DeleteVersionRequest(request)
diff --git a/google/cloud/appengine_admin_v1/services/versions/client.py b/google/cloud/appengine_admin_v1/services/versions/client.py
index 356b458..da022f2 100644
--- a/google/cloud/appengine_admin_v1/services/versions/client.py
+++ b/google/cloud/appengine_admin_v1/services/versions/client.py
@@ -839,9 +839,6 @@ def sample_delete_version():
 
                       }
 
-                   The JSON representation for Empty is empty JSON
-                   object {}.
-
         """
         # Create or coerce a protobuf request object.
         # Minor optimization to avoid making a copy if the user passes
diff --git a/noxfile.py b/noxfile.py
index 001ec73..70739b1 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -333,7 +333,8 @@ def prerelease_deps(session):
 
     # Install all dependencies
     session.install("-e", ".[all, tests, tracing]")
-    session.install(*UNIT_TEST_STANDARD_DEPENDENCIES)
+    unit_deps_all = UNIT_TEST_STANDARD_DEPENDENCIES + UNIT_TEST_EXTERNAL_DEPENDENCIES
+    session.install(*unit_deps_all)
     system_deps_all = (
         SYSTEM_TEST_STANDARD_DEPENDENCIES
         + SYSTEM_TEST_EXTERNAL_DEPENDENCIES
@@ -362,12 +363,6 @@ def prerelease_deps(session):
 
     session.install(*constraints_deps)
 
-    if os.path.exists("samples/snippets/requirements.txt"):
-        session.install("-r", "samples/snippets/requirements.txt")
-
-    if os.path.exists("samples/snippets/requirements-test.txt"):
-        session.install("-r", "samples/snippets/requirements-test.txt")
-
     prerel_deps = [
         "protobuf",
         # dependency of grpc
@@ -404,11 +399,19 @@ def prerelease_deps(session):
     system_test_folder_path = os.path.join("tests", "system")
 
     # Only run system tests if found.
-    if os.path.exists(system_test_path) or os.path.exists(system_test_folder_path):
-        session.run("py.test", "tests/system")
-
-    snippets_test_path = os.path.join("samples", "snippets")
-
-    # Only run samples tests if found.
-    if os.path.exists(snippets_test_path):
-        session.run("py.test", "samples/snippets")
+    if os.path.exists(system_test_path):
+        session.run(
+            "py.test",
+            "--verbose",
+            f"--junitxml=system_{session.python}_sponge_log.xml",
+            system_test_path,
+            *session.posargs,
+        )
+    if os.path.exists(system_test_folder_path):
+        session.run(
+            "py.test",
+            "--verbose",
+            f"--junitxml=system_{session.python}_sponge_log.xml",
+            system_test_folder_path,
+            *session.posargs,
+        )
diff --git a/setup.py b/setup.py
index ae4ea03..eccde45 100644
--- a/setup.py
+++ b/setup.py
@@ -20,14 +20,14 @@
 import setuptools  # type: ignore
 
 name = "google-cloud-appengine-admin"
-version = "1.5.0"
+version = "1.5.1"
 description = "App Engine Admin API client library"
 release_status = "Development Status :: 5 - Production/Stable"
 url = "https://github.com/googleapis/python-appengine-admin"
 dependencies = [
     "google-api-core[grpc] >= 1.32.0, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.*,!=2.4.*,!=2.5.*,!=2.6.*,!=2.7.*",
-    "proto-plus >= 1.18.1, <2.0.0dev",
-    "protobuf >= 3.19.0, <4.0.0dev",
+    "proto-plus >= 1.22.0, <2.0.0dev",
+    "protobuf >= 3.19.0, <5.0.0dev",
     "grpc-google-iam-v1 >=0.12.4, <1.0.0dev",
 ]
 
diff --git a/testing/constraints-3.7.txt b/testing/constraints-3.7.txt
index a25839e..75306b3 100644
--- a/testing/constraints-3.7.txt
+++ b/testing/constraints-3.7.txt
@@ -6,6 +6,6 @@
 # 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==1.32.0
-proto-plus==1.18.1
+proto-plus==1.22.0
 grpc-google-iam-v1==0.12.4
 protobuf==3.19.0