diff --git a/meshtastic/portnums.proto b/meshtastic/portnums.proto
index 918b063..ee5fd27 100644
--- a/meshtastic/portnums.proto
+++ b/meshtastic/portnums.proto
@@ -240,6 +240,13 @@ enum PortNum {
    */
   CAYENNE_APP = 77;
 
+  /*
+   * App for hydris protobuf, open source tactical sensor awareness,
+   * "home assistant for the outdoors"
+   * ENCODING: hydris protobuf
+   */
+  HYDRIS_APP = 78;
+
   /*
    * Private applications should use portnums >= 256.
    * To simplify initial development and testing you can use "PRIVATE_APP"