diff --git a/requirements.txt b/requirements.txt
index a0004c1..a497da9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,7 +4,7 @@ attrs>=20.3.0
 click>=7.1.2
 consolekit>=1.0.0
 domdf-python-tools>=2.5.0
-isort<=5.6.4,>=5.5.2
+isort>=5.5.2,<5.7.1
 toml>=0.10.2
 typing-extensions>=3.7.4.3
 yapf==0.30.0