diff --git a/requirements_dev.txt b/requirements_dev.txt
index f187d50..d1e4d05 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -7,5 +7,5 @@ tox==2.9.1
 coverage==4.4.2
 Sphinx==1.6.5
 cryptography==2.1.4
-PyYAML==3.12
+PyYAML==5.3.1