diff --git a/src/odrpack/result.py b/src/odrpack/result.py
index 954de45..d816aeb 100644
--- a/src/odrpack/result.py
+++ b/src/odrpack/result.py
@@ -7,7 +7,7 @@
 
 F64Array = NDArray[np.float64]
 I32Array = NDArray[np.int32]
-BoolArray = NDArray[np.bool]
+BoolArray = NDArray[bool]
 
 
 @dataclass(frozen=True)