diff --git a/flake.nix b/flake.nix
index 63a387a..b0ee00f 100644
--- a/flake.nix
+++ b/flake.nix
@@ -14,8 +14,11 @@
 
       systems = [ "x86_64-linux" "aarch64-linux" ];
 
-      perSystem = args@{ system, pkgs, lib, config, ... }: let
-        invoiceplane-template = pkgs.stdenv.mkDerivation {
+      perSystem = { config, pkgs, final, ... }: {
+        overlayAttrs = {
+          inherit (config.packages) invoiceplane-template;
+        };
+        packages.invoiceplane-template = pkgs.stdenv.mkDerivation {
           name = "invoiceplane-template";
           src = ./.;
           installPhase = '' 
@@ -23,12 +26,6 @@
             cp *.php $out/
           '';
         };
-      in {
-        packages.default = invoiceplane-template;
-        packages.invoiceplane-template = invoiceplane-template;
-        overlayAttrs = {
-          inherit (config.packages) invoiceplane-template;
-        };
       };
     };
 }