diff --git a/docs/releasenotes/9.0.0.rst b/docs/releasenotes/9.0.0.rst
index 39123012b94..4e6c3dca583 100644
--- a/docs/releasenotes/9.0.0.rst
+++ b/docs/releasenotes/9.0.0.rst
@@ -88,6 +88,15 @@ TODO
 API Additions
 =============
 
+ImageShow.XDGViewer
+^^^^^^^^^^^^^^^^^^^
+
+If `xdg-open` is present on Linux, this new :py:class:`PIL.ImageShow.Viewer` subclass
+will be registered. It displays images using the application selected by the system.
+
+It is higher in priority than the other default :py:class:`PIL.ImageShow.Viewer`
+instances, so it will be preferred by ``im.show()`` or :py:func:`.ImageShow.show()`.
+
 Added support for "title" argument to DisplayViewer
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^