diff --git a/Makefile b/Makefile
index d9ef8fa0..c73eca2d 100644
--- a/Makefile
+++ b/Makefile
@@ -40,7 +40,7 @@ clean:
 
 .PHONY: venv
 venv:
-	test -d $(VENV_DIR) || virtualenv -p $(PY3) $(VENV_DIR)
+	test -d $(VENV_DIR) || $(PY3) -m venv $(VENV_DIR)
 
 .PHONY: reqs
 reqs: venv
diff --git a/requirements.txt b/requirements.txt
index 1d5ca55a..e0ddb9ed 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ jsonschema!=2.5.0,<3.0.0,>=2.0.0 # MIT
 # networkx v2.6 does not support Python3.6.  Update networkx to match st2
 networkx>=2.5.1,<2.6
 python-dateutil
-PyYAML>=3.1.0 # MIT
+PyYAML>=3.1.0,<6.0 # MIT
 six>=1.9.0
 stevedore>=1.3.0 # Apache-2.0
 ujson>=1.35 # BSD License