diff --git a/docs/web_api.md b/docs/web_api.md
index fc17b0d..d29e869 100644
--- a/docs/web_api.md
+++ b/docs/web_api.md
@@ -3038,13 +3038,18 @@ Status Subscriptions arrive as a "notify_status_update" notification:
 {
     "jsonrpc": "2.0",
     "method": "notify_status_update",
-    "params": [{<status object>}]
+    "params": [{<status object>}, <eventtime>]
 }
 ```
 The structure of the `status object` is identical to the structure that is
 returned from an [object query's](#query-printer-object-status)
 `status` field.
 
+The `eventtime` is a timestamp generated by Klipper when
+the update was originally pushed.  This timestamp is a float value,
+relative to Klipper's monotonic clock.  Note that this value will be
+reset when Klipper restarts.
+
 #### Klippy Ready
 Notify clients when Klippy has reported a ready state
 ```json