diff --git a/requirements_dev.txt b/requirements_dev.txt
index b098e0e..2ad1d80 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -22,7 +22,7 @@ Jinja2==2.9.4 # via sphinx
 MarkupSafe==0.23          # via jinja2
 mccabe==0.6.1 # via flake8
 pathtools==0.1.2          # via watchdog
-pluggy==0.4.0 # via tox
+pluggy==0.5.2 # via tox
 py==1.4.32 # via pytest, tox
 pyasn1==0.1.9             # via cryptography
 pycodestyle==2.2.0 # via flake8