diff --git a/shp2citygml/requirements.txt b/shp2citygml/requirements.txt
index 1205dd7..14a3981 100644
--- a/shp2citygml/requirements.txt
+++ b/shp2citygml/requirements.txt
@@ -2,7 +2,7 @@ astroid==2.3.3
 certifi==2019.9.11
 isort==4.3.21
 lazy-object-proxy==1.4.3
-lxml==4.4.1
+lxml==4.6.3
 mccabe==0.6.1
 pylint==2.4.4
 pyshp==2.1.0