diff --git a/flake.nix b/flake.nix
index b787f78..7fd9b80 100644
--- a/flake.nix
+++ b/flake.nix
@@ -26,23 +26,25 @@
   outputs = { self, nixpkgs, nixpkgs-unstable, nixos-generators, sops-nix, ... }:
     let
       system = "x86_64-linux";
-      shairportSync431ExtendedNixpkgsUnstableOverlay = final: prev: {
-        shairport-sync = (prev.shairport-sync.override { enableMetadata = true; enableAirplay2 = true; }).overrideAttrs (finalAttr: previousAttr: {
-          # See: https://github.com/mikebrady/shairport-sync/blob/e78a88b64adfe7b5f88fd6faedf55c57445bb240/CONFIGURATION%20FLAGS.md
-          configureFlags = previousAttr.configureFlags ++ [ "--with-mqtt-client" ];
-          buildInputs = previousAttr.buildInputs ++ [ final.mosquitto ];
-        });
-      };
       pkgs-unstable = nixpkgs-unstable.legacyPackages."x86_64-linux";
     in
     {
+      overlays = {
+        shairportSyncAirplay2 = final: prev: {
+          shairport-sync = (prev.shairport-sync.override { enableMetadata = true; enableAirplay2 = true; }).overrideAttrs (finalAttr: previousAttr: {
+            # See: https://github.com/mikebrady/shairport-sync/blob/e78a88b64adfe7b5f88fd6faedf55c57445bb240/CONFIGURATION%20FLAGS.md
+            configureFlags = previousAttr.configureFlags ++ [ "--with-mqtt-client" ];
+            buildInputs = previousAttr.buildInputs ++ [ final.mosquitto ];
+          });
+        };
+      };
       nixosConfigurations = {
         audio-hauptraum-kueche = nixpkgs.lib.nixosSystem {
           inherit system;
           modules = [
             ./config/common
             ./config/proxmox-vm
-            { nixpkgs.overlays = [ shairportSync431ExtendedNixpkgsUnstableOverlay ]; }
+            { nixpkgs.overlays = [ self.overlays.shairportSyncAirplay2 ]; }
             ./config/hosts/audio-hauptraum-kueche
           ];
         };
@@ -52,7 +54,7 @@
           modules = [
             ./config/common
             ./config/proxmox-vm
-            { nixpkgs.overlays = [ shairportSync431ExtendedNixpkgsUnstableOverlay ]; }
+            { nixpkgs.overlays = [ self.overlays.shairportSyncAirplay2 ]; }
             ./config/hosts/audio-hauptraum-tafel
           ];
         };