diff --git a/modules/nix-common/default.nix b/modules/nix-common/default.nix
index ffef012..11e0769 100644
--- a/modules/nix-common/default.nix
+++ b/modules/nix-common/default.nix
@@ -19,7 +19,10 @@ in
         experimental-features = nix-command flakes 
       '';
 
-      autoOptimiseStore = true;
+      settings = {
+        auto-optimise-store = true;
+        allowed-users = [ "root" ];
+      };
 
       gc = {
         automatic = true;
@@ -27,7 +30,6 @@ in
         options = "--delete-older-than=30d";
       };
 
-      allowedUsers = [ "root" ];
     };
   };
 }
diff --git a/users/erwin/default.nix b/users/erwin/default.nix
index 02b635b..60c9008 100644
--- a/users/erwin/default.nix
+++ b/users/erwin/default.nix
@@ -13,5 +13,5 @@
     ];
   };
 
-  nix.allowedUsers = [ "erwin" ];
+  nix.settings.allowed-users = [ "erwin" ];
 }