diff --git a/pkgs/by-name/po/postfixadmin/package.nix b/pkgs/by-name/po/postfixadmin/package.nix
index 56b68ec9620287..488672707e3b8e 100644
--- a/pkgs/by-name/po/postfixadmin/package.nix
+++ b/pkgs/by-name/po/postfixadmin/package.nix
@@ -3,6 +3,9 @@
   stdenv,
   fetchFromGitHub,
   nixosTests,
+
+  configLocalPath ? "/etc/postfixadmin/config.local.php",
+  templatesCachePath ? "/var/cache/postfixadmin/templates_c",
 }:
 stdenv.mkDerivation (finalAttrs: {
   pname = "postfixadmin";
@@ -18,8 +21,8 @@ stdenv.mkDerivation (finalAttrs: {
   installPhase = ''
     mkdir $out
     cp -r * $out/
-    ln -sf /etc/postfixadmin/config.local.php $out/
-    ln -sf /var/cache/postfixadmin/templates_c $out/
+    ln -sf '${configLocalPath}' $out/config.local.php
+    ln -sf '${templatesCachePath}' $out/templates_c
   '';
 
   passthru.tests = { inherit (nixosTests) postfixadmin; };