diff --git a/requirements.txt b/requirements.txt
index 68dc843..f31d6c8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,7 +19,7 @@ hyperlink==18.0.0
 idna==2.7
 incremental==17.5.0
 kiwisolver==1.0.1
-lxml==4.2.6
+lxml==4.9.1
 matplotlib==3.0.1
 numpy==1.15.4
 oauth2client==4.1.3