diff --git a/nixos/modules/services/networking/nix-serve.nix b/nixos/modules/services/networking/nix-serve.nix
index 8c4352bc95e8..86bb603e1271 100644
--- a/nixos/modules/services/networking/nix-serve.nix
+++ b/nixos/modules/services/networking/nix-serve.nix
@@ -67,7 +67,9 @@ in
   };
 
   config = mkIf cfg.enable {
-    nix.settings.extra-allowed-users = [ "nix-serve" ];
+    nix.settings = lib.optionalAttrs (lib.versionAtLeast config.nix.package.version "2.4") {
+      extra-allowed-users = [ "nix-serve" ];
+    };
 
     systemd.services.nix-serve = {
       description = "nix-serve binary cache server";