diff --git a/flake.nix b/flake.nix
index 83881d4..58faa6e 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,7 +2,7 @@
   description = "Mastodon running in a container";
 
   inputs = {
-    nixpkgs.url = "nixpkgs/nixos-23.05";
+    nixpkgs.url = "nixpkgs/nixos-23.11";
     arion.url = "github:hercules-ci/arion";
   };
 
diff --git a/mastodon-container.nix b/mastodon-container.nix
index cf25ad6..b819939 100644
--- a/mastodon-container.nix
+++ b/mastodon-container.nix
@@ -44,6 +44,9 @@ in {
       default = 4;
     };
 
+    close-registrations =
+      mkEnableOption "Disable the creation of new accounts.";
+
     smtp = {
       host = mkOption {
         type = str;
@@ -105,7 +108,6 @@ in {
               configuration = {
                 boot.tmp.useTmpfs = true;
                 system.nssModules = mkForce [ ];
-                environment.systemPackages = with pkgs; [ dig inetutils ];
                 services = {
                   nscd.enable = false;
                   postgresql.enable = true;
@@ -126,6 +128,7 @@ in {
                     configureNginx = true;
                     automaticMigrations = true;
                     streamingProcesses = cfg.streaming-processes;
+                    extraConfig.registrations_open = !cfg.closed-registrations;
                   };
                   nginx = {
                     recommendedTlsSettings = true;