diff --git a/nixos/doc/manual/release-notes/rl-2105.xml b/nixos/doc/manual/release-notes/rl-2105.xml
index 9894ab025000..9e7ea70b9e7f 100644
--- a/nixos/doc/manual/release-notes/rl-2105.xml
+++ b/nixos/doc/manual/release-notes/rl-2105.xml
@@ -509,6 +509,15 @@ self: super:
      <varname>services.flashpolicyd</varname> module.
     </para>
    </listitem>
+   <listitem>
+    <para>
+      The <literal>security.rngd</literal> module has been removed.
+      It was disabled by default in 20.09 as it was functionally redundent
+      with krngd in the linux kernel. It is not necessary for any device that the kernel recognises
+      as an hardware RNG, as it will automatically run the krngd task to periodically collect random
+      data from the device and mix it into the kernel's RNG.
+    </para>
+   </listitem>
   </itemizedlist>
  </section>