diff --git a/requirements_dev.txt b/requirements_dev.txt
index 444ef67..ad744f7 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -6,5 +6,5 @@ tox==2.1.1
 coverage==4.0
 Sphinx==1.3.1
 cryptography==1.0.1
-PyYAML==3.11
+PyYAML==5.1