diff --git a/pybasicbayes/distributions/dynamic_glm.py b/pybasicbayes/distributions/dynamic_glm.py
index 5938ee53ab600728d0e4c85a73bc3c9b8fcd4516..e149ffec61d629dbf53568f5978453f1fd24fc58 100644
--- a/pybasicbayes/distributions/dynamic_glm.py
+++ b/pybasicbayes/distributions/dynamic_glm.py
@@ -167,7 +167,7 @@ class Dynamic_GLM(GibbsSampling):
 
         # R is the variance on the observations in Kalman filtering. According to Windle, that is 1 / omega here
         self.R = np.zeros(total_types)
-        mask = np.ones(total_types, dtype=np.bool)
+        mask = np.ones(total_types, dtype=bool)
         mask[fake_times] = False  # during fake times, we make no observations, so no variance
         self.R[mask] = 1 / omega