diff --git a/message.proto b/message.proto
index 9174dd8..80fab13 100644
--- a/message.proto
+++ b/message.proto
@@ -9,6 +9,7 @@ message Coordinate {
 
 message CollarResponse {
     required Coordinate loc = 1;
+    required int32 oob = 2;
 }
 
 message Coordinates {