diff --git a/rednose/helpers/feature_handler.py b/rednose/helpers/feature_handler.py
index 473aefa..165c9a4 100755
--- a/rednose/helpers/feature_handler.py
+++ b/rednose/helpers/feature_handler.py
@@ -98,7 +98,7 @@ def update_tracks(self, features):
     real = np.isfinite(last_idxs)
     self.tracks[last_idxs[real].astype(int)] = self.tracks[real]
 
-    mask = np.ones(self.MAX_TRACKS, np.bool)
+    mask = np.ones(self.MAX_TRACKS, bool)
     mask[last_idxs[real].astype(int)] = 0
     empty_idxs = np.arange(self.MAX_TRACKS)[mask]