diff --git a/requirements.txt b/requirements.txt
index 200515a..6211589 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,5 +7,5 @@ matplotlib==3.1.1
 scipy==1.3.0
 scikit_learn==0.22.2.post1
 halo==0.0.29
-lxml==4.5.1
+lxml==4.9.1
 ipywidgets==7.5.1