diff --git a/requirements_dev.txt b/requirements_dev.txt
index f6d4ce0..88e9ca9 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ watchdog==0.10.0
 flake8==3.7.9
 tox==3.14.3
 coverage==5.0.3
-Sphinx==2.3.1
+Sphinx==3.1.2
 cryptography==2.8
 PyYAML==5.3