diff --git a/changes/217.misc.rst b/changes/217.misc.rst
new file mode 100644
index 0000000..4ac1456
--- /dev/null
+++ b/changes/217.misc.rst
@@ -0,0 +1 @@
+Updated tox from 4.20.0 to 4.21.2.
diff --git a/pyproject.toml b/pyproject.toml
index 34b5aba..1f2691c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -49,7 +49,7 @@ dev = [
     "pre-commit == 4.0.0 ; python_version >= '3.9'",
     "pytest == 8.3.3",
     "setuptools_scm == 8.1.0",
-    "tox == 4.20.0",
+    "tox == 4.21.2",
 ]
 
 [project.urls]