diff --git a/service/src/main/proto/TextSecure.proto b/service/src/main/proto/TextSecure.proto
index f0100dc84..d8c80196d 100644
--- a/service/src/main/proto/TextSecure.proto
+++ b/service/src/main/proto/TextSecure.proto
@@ -42,6 +42,7 @@ message Envelope {
   optional string serverGuid = 9;
   optional uint64 server_timestamp = 10;
   optional bool ephemeral = 12; // indicates that the message should not be persisted if the recipient is offline
+  optional string destinationUuid = 13;
 }
 
 message ProvisioningUuid {