diff --git a/docs/v1/P4Runtime-Spec.mdk b/docs/v1/P4Runtime-Spec.mdk
index c1124ed7..f08938b1 100755
--- a/docs/v1/P4Runtime-Spec.mdk
+++ b/docs/v1/P4Runtime-Spec.mdk
@@ -2298,6 +2298,8 @@ preserved, it will be explicitly stated in this document. The
 C++ API supports comparing messages while treating repeated fields as sets, so
 that different orderings of the same elements are considered equal. This method
 of comparing Protobuf messages may come at a cost in performance.
+The `backup_replicas` must be returned in order when read to preserve the
+sequence of highest-preferred backup replicas.
 
 ### Data plane volatile objects { #sec-data-plane-volatile-objects }