diff --git a/requirements_dev.txt b/requirements_dev.txt
index 49516b3..6284195 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ watchdog==2.0.2
 flake8==3.9.0
 tox==3.23.0
 coverage==5.5
-Sphinx==3.4.3
+Sphinx==3.5.3
 cryptography==3.4.6
 PyYAML==5.4.1
 pytest==6.2.3