diff --git a/server/storage/schema/schema.go b/server/storage/schema/schema.go
index 0f54c04fabe..b87b73cc831 100644
--- a/server/storage/schema/schema.go
+++ b/server/storage/schema/schema.go
@@ -95,6 +95,12 @@ func UnsafeDetectSchemaVersion(lg *zap.Logger, tx backend.UnsafeReader) (v semve
 	if vp != nil {
 		return *vp, nil
 	}
+
+	// TODO: remove the operations of reading the fields `confState`
+	// and `term` in 3.7. We only need to be back-compatible
+	// with 3.6 when we are running 3.7, and the `storageVersion`
+	// already exists in all versions >= 3.6, so we don't need to
+	// use any other fields to identify the etcd's storage version.
 	confstate := UnsafeConfStateFromBackend(lg, tx)
 	if confstate == nil {
 		return v, fmt.Errorf("missing confstate information")