diff --git a/requirements.txt b/requirements.txt
index 06639cb..a489b5c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -23,7 +23,7 @@ pickleshare==0.7.2
 port-for==0.3.1
 ptyprocess==0.5.1
 pydicom==0.9.9
-Pygments==2.2.0
+Pygments==2.7.4
 pytz==2017.2
 PyYAML==3.12
 requests==2.17.3