diff --git a/docs/requirements.txt b/docs/requirements.txt
index 96391ff7..abbde9ca 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,6 +1,6 @@
 Jinja2==2.11.3
 MarkupSafe==1.1.1
-Pygments==2.7.4
+Pygments==1.6
 Sphinx==1.2.2
 argparse==1.2.1
 docutils==0.11