diff --git a/docs/pyMCell/requirements.txt b/docs/pyMCell/requirements.txt
index 87036af85..d6e71177d 100644
--- a/docs/pyMCell/requirements.txt
+++ b/docs/pyMCell/requirements.txt
@@ -8,7 +8,7 @@ imagesize==1.0.0
 Jinja2==2.10
 MarkupSafe==1.0
 packaging==16.8
-Pygments==2.2.0
+Pygments==2.7.4
 pyparsing==2.2.0
 pytz==2018.3
 requests==2.18.4