diff --git a/requirements.txt b/requirements.txt
index 53a1f73..e26d4f8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -17,7 +17,7 @@ ipaddress==1.0.18
 itsdangerous==0.24
 Jinja2==2.8
 klein==16.12.0
-lxml==3.7.1
+lxml==4.6.5
 MarkupSafe==0.23
 matplotlib==1.5.1
 networkx==1.11