diff --git a/objects/instant-message/definition.json b/objects/instant-message/definition.json
index 0c54e8f..d60d17a 100644
--- a/objects/instant-message/definition.json
+++ b/objects/instant-message/definition.json
@@ -22,7 +22,8 @@
         "Discord",
         "Mumble",
         "Jabber",
-        "Twitter"
+        "Twitter",
+        "Mattermost"
       ],
       "ui-priority": 1
     },
@@ -118,4 +119,4 @@
   ],
   "uuid": "5fa51a24-f40f-4696-a77e-d31e26bab5fc",
   "version": 3
-}
\ No newline at end of file
+}