diff --git a/nixos/doc/manual/release-notes/rl-1903.xml b/nixos/doc/manual/release-notes/rl-1903.xml
index 1f26d4765b9..7a393edb8fb 100644
--- a/nixos/doc/manual/release-notes/rl-1903.xml
+++ b/nixos/doc/manual/release-notes/rl-1903.xml
@@ -105,6 +105,14 @@
      <varname>rabbitmq-server</varname>.
     </para>
    </listitem>
+   <listitem>
+     <para>
+       The <literal>light</literal> module no longer use setuids binary, but
+       udev rules. As a consequence users of that module have to belong to the
+       <literal>video</literal> group in order to use the executable
+       (i.e. <literal>users.users.yourusername.extraGroups = ["video"];</literal>).
+     </para>
+   </listitem>
   </itemizedlist>
  </section>