diff --git a/requirements.txt b/requirements.txt
index f08a6c08..25698f9c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 cryptography==2.3.1
 jsonschema==2.6.0
-lxml==4.2.1
+lxml==4.4.0
 ndg-httpsclient==0.5.0
 pyasn1==0.4.3
 pyOpenSSL==18.0.0