diff --git a/.github/.OwlBot.lock.yaml b/.github/.OwlBot.lock.yaml
index 58fcbee..0eb02fd 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: sha256:9db98b055a7f8bd82351238ccaacfd3cda58cdf73012ab58b8da146368330021
+# created: 2022-07-25T16:02:49.174178716Z
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9b87668..b39fc81 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## [2.9.1](https://github.com/googleapis/python-containeranalysis/compare/v2.9.0...v2.9.1) (2022-08-12)
+
+
+### Bug Fixes
+
+* **deps:** allow protobuf < 5.0.0 ([#310](https://github.com/googleapis/python-containeranalysis/issues/310)) ([6f2622f](https://github.com/googleapis/python-containeranalysis/commit/6f2622faff8b7b8b3a62936ec43641058084d0e5))
+* **deps:** require proto-plus >= 1.22.0 ([6f2622f](https://github.com/googleapis/python-containeranalysis/commit/6f2622faff8b7b8b3a62936ec43641058084d0e5))
+
 ## [2.9.0](https://github.com/googleapis/python-containeranalysis/compare/v2.8.1...v2.9.0) (2022-07-16)
 
 
diff --git a/noxfile.py b/noxfile.py
index 8119cc4..6019f75 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/samples/snippets/requirements.txt b/samples/snippets/requirements.txt
index 946a871..4b2c127 100644
--- a/samples/snippets/requirements.txt
+++ b/samples/snippets/requirements.txt
@@ -1,6 +1,6 @@
-google-cloud-pubsub==2.13.1
-google-cloud-containeranalysis==2.8.1
-grafeas==1.4.5
+google-cloud-pubsub==2.13.6
+google-cloud-containeranalysis==2.9.0
+grafeas==1.5.0
 pytest==7.1.2
 flaky==3.7.0
 mock==4.0.3
diff --git a/setup.py b/setup.py
index 768fd12..6a31474 100644
--- a/setup.py
+++ b/setup.py
@@ -22,13 +22,13 @@
 
 name = "google-cloud-containeranalysis"
 description = "Container Analysis API API client library"
-version = "2.9.0"
+version = "2.9.1"
 release_status = "Development Status :: 5 - Production/Stable"
 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.*",
     "grpc-google-iam-v1 >= 0.12.4, <1.0.0dev",
-    "proto-plus >= 1.15.0, <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",
     "grafeas >=1.4.1, <2.0dev",
 ]
 extras = {"libcst": "libcst >= 0.2.5"}
diff --git a/testing/constraints-3.7.txt b/testing/constraints-3.7.txt
index 150be7f..31e0c08 100644
--- a/testing/constraints-3.7.txt
+++ b/testing/constraints-3.7.txt
@@ -7,7 +7,7 @@
 # Then this file should have foo==1.14.0
 google-api-core==1.32.0
 grpc-google-iam-v1==0.12.4
-proto-plus==1.15.0
+proto-plus==1.22.0
 libcst==0.2.5
 grafeas==1.4.1
 protobuf==3.19.0