diff --git a/requirements_dev.txt b/requirements_dev.txt
index dec227d..6f7b6e2 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -3,7 +3,7 @@
 flake8==3.8.4
 pip==21.0.1
 pytest==6.2.2
-Sphinx==3.4.3
-tox==3.21.3
+Sphinx==3.5.1
+tox==3.22.0
 twine==3.3.0
 wheel==0.36.2