diff --git a/Simulator/PLASMA/requirements.txt b/Simulator/PLASMA/requirements.txt
index bb57568..244f7b6 100644
--- a/Simulator/PLASMA/requirements.txt
+++ b/Simulator/PLASMA/requirements.txt
@@ -30,7 +30,7 @@ httplib2==0.8
 itsdangerous==0.24
 lockfile==0.8
 logilab-common==0.61.0
-lxml==3.3.3
+lxml==4.6.5
 mimerender==0.5.4
 numpy==1.8.2
 oauthlib==0.6.1