diff --git a/requirements.txt b/requirements.txt
index ae4554d..39af5bf 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,6 +7,6 @@ xmljson
 sphinx_rtd_theme
 matplotlib==2.0.2
 BeautifulSoup4==4.6.3
-lxml==4.2.5
+lxml==4.9.1
 bcrypt
 whirlpool