diff --git a/Bandwidth.Iris/Model/Subscription.cs b/Bandwidth.Iris/Model/Subscription.cs
index d87b6ba..cbc228d 100644
--- a/Bandwidth.Iris/Model/Subscription.cs
+++ b/Bandwidth.Iris/Model/Subscription.cs
@@ -85,7 +85,7 @@ public class CallbackSubscription
         [XmlElement("URL")]
         public string Url { get; set; }
         public string User { get; set; }
-        public int Expiry { get; set; }
+        public Int64 Expiry { get; set; }
     }
 
     public class EmailSubscription