diff --git a/requirements.in b/requirements.in
index 9f6e0cf..1871696 100644
--- a/requirements.in
+++ b/requirements.in
@@ -10,4 +10,4 @@ pytest-cov
 Sphinx<4.4  # otherwise importlib-metadata dependency bites with flake8
 tox
 twine
-virtualenv<20.16.3  # otherwise importlib-metadata dependency bites with flake8. this is a dependency of tox.
+virtualenv<20.25.2  # otherwise importlib-metadata dependency bites with flake8. this is a dependency of tox.