diff --git a/requirements.txt b/requirements.txt
index 5e5da78..ca1f2fa 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -17,7 +17,7 @@ idna==2.8
 itypes==1.1.0
 jdcal==1.4.1
 Jinja2==2.10.1
-lxml==4.4.1
+lxml==4.9.1
 MarkupSafe==1.1.1
 msgpack==0.6.2
 odfpy==1.4.0