diff --git a/docs/requirements.txt b/docs/requirements.txt
index 45de2340..559f8a92 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -2,5 +2,5 @@ Sphinx==1.4.4
 sphinx-argparse==0.1.15
 sphinx_rtd_theme==0.1.9
 matplotlib==2.2.4
-#PyYAML==5.1
+PyYAML>=6.0
 mock>=2.0.0