diff --git a/requirements.txt b/requirements.txt
old mode 100755
new mode 100644
index bd866e0..e1dd0ba
--- a/requirements.txt
+++ b/requirements.txt
@@ -44,7 +44,7 @@ jupyter-client==5.2.3
 jupyter-console==5.2.0
 jupyter-core==4.4.0
 kiwisolver==1.0.1
-lxml==4.2.3
+lxml==4.9.1
 Markdown==2.6.11
 MarkupSafe==1.0
 matplotlib==2.2.2