diff --git a/python/pyproject.toml b/python/pyproject.toml
index 7e3575d..af4cc55 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -9,7 +9,7 @@ description = "Library and tools for working with PET Emission Tomography Standa
 readme = "README.md"
 authors = [{ name = "Kris Thielemans", email = "k.thielemans@ucl.ac.uk" }]
 license = { text = "Apache-2.0" }  # Update as needed
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dependencies = [
-    "numpy>=1.24.3",
+    "numpy>=1.22",
 ]