diff --git a/pyproject.toml b/pyproject.toml
index 6e4bf5b..cc9ef63 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -48,7 +48,7 @@ classifiers = [
 
 [project.optional-dependencies]
 docker = [
-  "tox==4.19.0"
+  "tox==4.21.1"
 ]
 
 dev = [