diff --git a/requirements.txt b/requirements.txt
index a765916..2a24e7f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-matplotlib>=3.4.1,<4
+matplotlib>=3.4.1,<3.7
 mypy>=0.782
 numpy>=1.20.2,<2
 pandas>=1.1.2,<2