diff --git a/requirements.txt b/requirements.txt
index e16fad0..4d1140c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,7 +8,7 @@ json-spec==0.10.1
 jsonmerge==1.3.0
 jsonschema==2.6.0
 lockfile==0.12.2
-lxml==3.7.3
+lxml==4.9.1
 mistune==0.7.4
 nltk==3.2.4
 numpy==1.12.1