diff --git a/nixos/doc/manual/release-notes/rl-1703.xml b/nixos/doc/manual/release-notes/rl-1703.xml
index 09358f3af231..be6ad59ac5d7 100644
--- a/nixos/doc/manual/release-notes/rl-1703.xml
+++ b/nixos/doc/manual/release-notes/rl-1703.xml
@@ -46,6 +46,7 @@ following incompatible changes:</para>
       for what those parameters represent.
     </para>
   </listitem>
+
   <listitem>
     <para>
       <literal>ansible</literal> now defaults to ansible version 2 as version 1
@@ -54,6 +55,7 @@ following incompatible changes:</para>
       vulnerability</link> unpatched by upstream.
     </para>
   </listitem>
+
   <listitem>
     <para>
       <literal>gnome</literal> alias has been removed along with
@@ -116,7 +118,6 @@ following incompatible changes:</para>
   </listitem>
 
   <listitem>
-
     <para><literal>overridePackages</literal> function no longer exists.
     It is replaced by <link
     xlink:href="https://nixos.org/nixpkgs/manual/#sec-overlays-install">
@@ -153,6 +154,15 @@ following incompatible changes:</para>
     </para>
   </listitem>
 
+  <listitem>
+    <para>
+      <literal>local_recipient_maps</literal> is not set to empty value by
+      Postfix service. It's an insecure default as stated by Postfix
+      documentation. Those who want to retain this setting need to set it via
+      <literal>services.postfix.extraConfig</literal>.
+    </para>
+  </listitem>
+
 </itemizedlist>
 
 
diff --git a/nixos/modules/services/mail/postfix.nix b/nixos/modules/services/mail/postfix.nix
index cdde41446224..caaa87b94d61 100644
--- a/nixos/modules/services/mail/postfix.nix
+++ b/nixos/modules/services/mail/postfix.nix
@@ -79,8 +79,6 @@ let
       relay_domains = ${concatStringsSep ", " cfg.relayDomains}
     ''
     + ''
-      local_recipient_maps =
-
       relayhost = ${if cfg.lookupMX || cfg.relayHost == "" then
           cfg.relayHost
         else