diff --git a/requirements_dev.txt b/requirements_dev.txt
index 19506027..cc1948d2 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -2,7 +2,7 @@
 FireWorks==1.8.7
 GitPython==2.1.11
 black==19.3b0
-flake8==3.7.8
+flake8==3.9.1
 isort==4.3.21
 pre-commit==1.18.3
 paramiko==2.6.0