diff --git a/requirements.txt b/requirements.txt
index 604f40b..9435aba 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,4 +2,4 @@
 -r requirements-qa.txt
 -r requirements-test.txt
 sphinx_rtd_theme==0.5.1
-tox==3.21.3
+tox==3.21.4