diff --git a/requirements_dev.txt b/requirements_dev.txt
index c4c5d39..74f2a07 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ pytest-cov==2.10.1
 executor>=21.0
 click>=7.0,<8.0
 
-flake8>=3.7.7,<4.0
+flake8>=3.7.7,<7.0
 flake8-import-order >=0.18.1,<0.19
 flake8-pyi>=20.5.0,<21.0.0
 black==20.8b1