diff --git a/pyproject.toml b/pyproject.toml
index 1aa7f99..e19b1d1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,7 +24,7 @@ requires-python = ">=3.8"
 dependencies = [
     "numpy<2; python_version<='3.8'",
     "numpy; python_version>'3.8'",
-    "scipy",
+    "scipy<1.15", # some interpolate._bspl internals removed
 ]
 
 [project.optional-dependencies]