diff --git a/pyproject.toml b/pyproject.toml
index e14f2e61..2fa99d97 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -10,7 +10,7 @@ python = "^3.7"
 numpy = "^1.10.1"
 scipy = "^1.0.0"
 pandas = "^1.0.0"
-matplotlib = "^3.3.4"
+matplotlib = "^3.2.2"
 requests = "^2.8.1"
 pytest = {version = "^7.1.1", optional = true}
 pytest-xdist = {version = "^2.5.0", optional = true}