diff --git a/docs/metrics.md b/docs/metrics.md
index 035a57fa..54d27deb 100644
--- a/docs/metrics.md
+++ b/docs/metrics.md
@@ -112,6 +112,7 @@ Fired whenever a user deletes a file they’ve uploaded.
 - `cm6`
 - `cm7`
 - `cd1`
+- `cd4`
 
 #### `copied`
 Fired whenever a user copies the URL of an upload file.