diff --git a/content/en/docs/concepts/storage/volumes.md b/content/en/docs/concepts/storage/volumes.md
index 729f7382d33a2..100ee56f717f9 100644
--- a/content/en/docs/concepts/storage/volumes.md
+++ b/content/en/docs/concepts/storage/volumes.md
@@ -1158,7 +1158,7 @@ spec:
 
 
 Use the `subPathExpr` field to construct `subPath` directory names from Downward API environment variables.
-This feature is enabled by default.
+This feature requires `VolumeSubpathEnvExpansion` feature gate to be enabled. It is enabled by default starting with Kubernetes 1.15.
 The `subPath` and `subPathExpr` properties are mutually exclusive.
 
 In this example, a Pod uses `subPathExpr` to create a directory `pod1` within the hostPath volume `/var/log/pods`, using the pod name from the Downward API.  The host directory `/var/log/pods/pod1` is mounted at `/logs` in the container.