diff --git a/requirements_dev.txt b/requirements_dev.txt
index 0e75d5c..9b17b9e 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -6,7 +6,7 @@ flake8==4.0.1
 tox==3.24.4
 coverage==6.2
 cryptography==3.4.8
-Sphinx==4.3.0
+Sphinx==4.3.1
 PyYAML==5.4.1
 pytest==6.2.5
 pytest-runner==5.3.1