diff --git a/requirements.txt b/requirements.txt
index 6cb0e13..b7a5dd9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -56,7 +56,7 @@ javapackages==1.0.0
 kitchen==1.1.1
 langtable==0.0.27
 lockfile==0.9.1
-lxml==3.3.6
+lxml==4.9.1
 matplotlib==1.3.1
 mercurial==2.8.1
 mglob==0.4