diff --git a/py/pyproject.toml b/py/pyproject.toml
index ea7f0c7..59b84ea 100644
--- a/py/pyproject.toml
+++ b/py/pyproject.toml
@@ -9,7 +9,7 @@ authors = [{name = "Milan Skocic", email = "milan.skocic@icloud.com"}]
 description = "pyiapws: IAPWS for python."
 readme = "README.md"
 requires-python = ">=3.9"
-dependencies  = ["numpy>=1.21"]
+dependencies  = ["numpy>=1.25"]
 license = {text = "MIT"}
 classifiers=["Development Status :: 5 - Production/Stable",
              "Intended Audience :: Science/Research",