diff --git a/service/src/main/proto/TextSecure.proto b/service/src/main/proto/TextSecure.proto
index 9ad7cf127..17c3bc4af 100644
--- a/service/src/main/proto/TextSecure.proto
+++ b/service/src/main/proto/TextSecure.proto
@@ -35,7 +35,11 @@ message Envelope {
   optional bool story = 16; // indicates that the content is a story.
   optional bytes report_spam_token = 17; // token sent when reporting spam
   optional bytes shared_mrm_key = 18; // indicates content should be fetched from multi-recipient message datastore
-  // next: 19
+  optional bytes source_service_id_binary = 19; // service ID binary (i.e. 16 byte UUID for ACI, 1 byte prefix + 16 byte UUID for PNI)
+  optional bytes destination_service_id_binary = 20; // service ID binary (i.e. 16 byte UUID for ACI, 1 byte prefix + 16 byte UUID for PNI)
+  optional bytes server_guid_binary = 21; // 16-byte UUID
+  optional bytes updated_pni_binary = 22; // 16-byte UUID
+  // next: 22
 }
 
 message ProvisioningAddress {