diff --git a/setup.cfg b/setup.cfg
index bdaff62..441a6fb 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -107,7 +107,7 @@ dev =
     types-requests~=2.32.0.20240914
     types-six~=1.16.21.20240513
     types-waitress~=3.0.0.20240423
-    virtualenv~=20.24.3
+    virtualenv~=21.6.1
 
 # 👉 Note: The ``-stubs`` and ``types-`` dependencies above ↑ in the ``dev``
 # extra must be duplicated in ``.pre-commit-config.yaml`` in order for ``tox``