diff --git a/requirements_dev.txt b/requirements_dev.txt
index 5ab5b7b..73e5889 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ watchdog==0.8.3
 flake8==3.5.0
 tox==2.7.0
 coverage==4.4.1
-Sphinx==1.7.2
+Sphinx==3.4.0
 cryptography==1.9
 PyYAML==3.12