diff --git a/virtualenv/optecs-python36/requirements.txt b/virtualenv/optecs-python36/requirements.txt
index 5ac6ff4..2493067 100644
--- a/virtualenv/optecs-python36/requirements.txt
+++ b/virtualenv/optecs-python36/requirements.txt
@@ -7,7 +7,7 @@ cx-Freeze==5.0.1
 defusedxml==0.4.1
 isodate==0.5.4
 keyring==10.2
-lxml==4.6.3
+lxml==4.9.1
 mypy==0.521
 peewee==2.8.5
 pygame==1.9.3