diff --git a/lib/ash/resource/actions/update.ex b/lib/ash/resource/actions/update.ex
index c0d04b73..9776d9a2 100644
--- a/lib/ash/resource/actions/update.ex
+++ b/lib/ash/resource/actions/update.ex
@@ -79,7 +79,7 @@ defmodule Ash.Resource.Actions.Update do
                   default: false
                 ],
                 atomic_upgrade_with: [
-                  type: {:one_of, [:atom, nil]},
+                  type: {:or, [:atom, nil]},
                   doc: """
                   Configure the read action used when performing atomic upgrades. Defaults to the primary read action.
                   """