diff --git a/aprsd/packets/tracker.py b/aprsd/packets/tracker.py
index 09ed0ca..d848712 100644
--- a/aprsd/packets/tracker.py
+++ b/aprsd/packets/tracker.py
@@ -88,7 +88,7 @@ class PacketTrack(objectstore.ObjectStoreMixin):
             self._remove(packet.msgNo)
         elif isinstance(packet, core.RejectPacket):
             self._remove(packet.msgNo)
-        elif packet.ackMsgNo:
+        elif hasattr(packet, "ackMsgNo"):
             # Got a piggyback ack, so remove the original message
             self._remove(packet.ackMsgNo)