diff --git a/uspto-patents/code-env/python/spec/requirements.txt b/uspto-patents/code-env/python/spec/requirements.txt
index 5f7ea63b..ef050ea4 100644
--- a/uspto-patents/code-env/python/spec/requirements.txt
+++ b/uspto-patents/code-env/python/spec/requirements.txt
@@ -1 +1 @@
-lxml==3.3.4
+lxml==4.9.1