diff --git a/requirements.txt b/requirements.txt
index 2486085f..a1772cc6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ networkx==2.3
 numpy==1.16.3
 PuLP==1.6.9
 pytest==4.4.1
-PyYAML==5.1
+PyYAML==5.4
 requests==2.21.0
 Sphinx==2.0.1
 sphinx-rtd-theme==0.4.3