diff --git a/pyproject.toml b/pyproject.toml
index 77c7184..b902dbf 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,11 @@ requires = [
     "wheel",
     "Cython>=3.0a7",
     "setuptools_scm[toml]>=6.2",
-    "oldest-supported-numpy"
+    # Note for packagers: this constraint is specific to wheels
+    # for PyPI; it is also supported to build against 1.xx still.
+    # If you do so, please ensure to include a `numpy<2.0`
+    # runtime requirement for those binary packages.
+    "numpy>=2.0.0rc1"
 ]
 build-backend = "setuptools.build_meta"