diff --git a/requirements_dev.txt b/requirements_dev.txt
index b146bf2..968fcb0 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -7,5 +7,5 @@ tox==2.7.0
 coverage==4.4.1
 Sphinx==1.6.3
 cryptography==2.0.2
-PyYAML==3.12
+PyYAML==6.0.1