diff --git a/bilby/core/utils/io.py b/bilby/core/utils/io.py
index b6e9b79c5a7bccad09cb7e50d93998c0fc75fea1..80590faf4ceb49b697ad0aa1747a2e1ba242cd2f 100644
--- a/bilby/core/utils/io.py
+++ b/bilby/core/utils/io.py
@@ -264,9 +264,9 @@ def encode_for_hdf5(key, item):
 
     if isinstance(item, np.int_):
         item = int(item)
-    elif isinstance(item, np.float_):
+    elif isinstance(item, np.float64):
         item = float(item)
-    elif isinstance(item, np.complex_):
+    elif isinstance(item, np.complex128):
         item = complex(item)
     if isinstance(item, np.ndarray):
         # Numpy's wide unicode strings are not supported by hdf5
diff --git a/bilby/gw/prior.py b/bilby/gw/prior.py
index 81dd2d557133feb39332e536907d065deead55c8..5e9f670d5acb0fa7c8bf5de0519dad6ca9e6d87b 100644
--- a/bilby/gw/prior.py
+++ b/bilby/gw/prior.py
@@ -1436,7 +1436,7 @@ class HealPixMapPriorDist(BaseJointPriorDist):
                 self.update_distance(int(round(val)))
                 dist_samples[i] = self.distance_icdf(dist_samp[i])
         if self.distance:
-            sample = np.row_stack([sample[:, 0], sample[:, 1], dist_samples])
+            sample = np.vstack([sample[:, 0], sample[:, 1], dist_samples])
         return sample.reshape((-1, self.num_vars))
 
     def update_distance(self, pix_idx):