diff --git a/nixos/doc/manual/release-notes/rl-1903.xml b/nixos/doc/manual/release-notes/rl-1903.xml
index 931c3be5913..a82724d7fb5 100644
--- a/nixos/doc/manual/release-notes/rl-1903.xml
+++ b/nixos/doc/manual/release-notes/rl-1903.xml
@@ -216,13 +216,6 @@
       <literal>[]</literal>.
     </para>
    </listitem>
-   <listitem>
-    <para>
-      The NetworkManager systemd unit was renamed back from network-manager.service to
-      NetworkManager.service for better compatibility with other applications expecting this name.
-      The same applies to ModemManager where modem-manager.service is now called ModemManager.service again.
-    </para>
-   </listitem>
    <listitem>
     <para>
      Package <varname>rabbitmq_server</varname> is renamed to
diff --git a/nixos/doc/manual/release-notes/rl-1909.xml b/nixos/doc/manual/release-notes/rl-1909.xml
index f54592b6bf6..925dadcb03d 100644
--- a/nixos/doc/manual/release-notes/rl-1909.xml
+++ b/nixos/doc/manual/release-notes/rl-1909.xml
@@ -42,6 +42,29 @@
   </itemizedlist>
  </section>
 
+ <section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="sec-release-19.09-incompatibilities">
+  <title>Backward Incompatibilities</title>
+
+  <para>
+   When upgrading from a previous release, please be aware of the following
+   incompatible changes:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+      The NetworkManager systemd unit was renamed back from network-manager.service to
+      NetworkManager.service for better compatibility with other applications expecting this name.
+      The same applies to ModemManager where modem-manager.service is now called ModemManager.service again.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </section>
+
  <section xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xmlns:xi="http://www.w3.org/2001/XInclude"