diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 100d563284e5..6d554a95589c 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -356,7 +356,9 @@ well.
 
 =item *
 
-XXX
+The XS parser, L<ExtUtils::ParseXS>, has been extensively restructured
+internally. Most of these changes shouldn't be visible externally, but
+might affect XS code which was using invalid or unsupported syntax.
 
 =back