diff --git a/noxfile.py b/noxfile.py
index 0bd7f6c..236b59c 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -69,13 +69,14 @@
     )
 
 
-@nox.session(python="3.6")
+@nox.session(python="3.8")
 def blacken(session):
     """Run black.
     Format code to uniform standard.
-    This currently uses Python 3.6 due to the automated Kokoro run of synthtool.
-    That run uses an image that doesn't have 3.6 installed. Before updating this
-    check the state of the `gcp_ubuntu_config` we use for that Kokoro run.
+    The Python version should be consistent with what is
+    supplied in the Python Owlbot postprocessor.
+
+    https://github.com/googleapis/synthtool/blob/master/docker/owlbot/python/Dockerfile
     """
     session.install(BLACK_VERSION)
     session.run("black", *BLACK_PATHS)
diff --git a/setup.py b/setup.py
index ef723f8..f2fd4e5 100644
--- a/setup.py
+++ b/setup.py
@@ -31,7 +31,11 @@
 )
 
 extras = {
-    "aiohttp": "aiohttp >= 3.6.2, < 4.0.0dev; python_version>='3.6'",
+    "aiohttp": [
+        "aiohttp >= 3.6.2, < 4.0.0dev; python_version>='3.6'",
+        "requests >= 2.18.0, < 3.0.0dev",
+        "urllib3 >= 1.0.0, <2.0.0dev",
+    ],
     "pyopenssl": "pyopenssl>=20.0.0",
     "reauth": "pyu2f>=0.1.5",
 }
diff --git a/testing/constraints-3.6.txt b/testing/constraints-3.6.txt
index ff7f099..7cb802a 100644
--- a/testing/constraints-3.6.txt
+++ b/testing/constraints-3.6.txt
@@ -11,4 +11,6 @@
 six==1.9.0
 rsa==4.6
 rsa==3.1.4
-aiohttp==3.6.2
\ No newline at end of file
+aiohttp==3.6.2
+requests==2.18.0
+urllib3==1.0.0