diff --git a/stimulus/requirements.txt b/stimulus/requirements.txt
index abfbb4c..544a533 100644
--- a/stimulus/requirements.txt
+++ b/stimulus/requirements.txt
@@ -56,7 +56,7 @@ python-bidi==0.4.0
 python-dateutil==2.8.0
 python-gitlab==1.8.0
 pytz==2018.9
-PyYAML==5.1
+PyYAML==5.4
 pyzmq==18.0.1
 requests==2.21.0
 scipy==1.2.1