diff --git a/telemetry/definitions/commonDefinitions.json b/telemetry/definitions/commonDefinitions.json
index dc309254..31339d34 100644
--- a/telemetry/definitions/commonDefinitions.json
+++ b/telemetry/definitions/commonDefinitions.json
@@ -2894,6 +2894,10 @@
                 {
                     "type": "result"
                 },
+                {
+                    "type": "sessionDuration",
+                    "required": false
+                },
                 {
                     "type": "source"
                 },