diff --git a/requirements-dev.txt b/requirements-dev.txt
index 06d97a0..6f8d007 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -9,7 +9,7 @@ matplotlib>=3.3.0
 sphinx-hoverxref
 sphinx-rtd-theme>=1.0.0
 sphinx-design>=0.3.0
-graphviz>=0.20.1
+graphviz>=0.21
 pytest>=7.0.0
 pytest-cov>=4.0.0
 black>=23.0.0