diff --git a/Networks/raspberry_pi_rack.nix b/Networks/raspberry_pi_rack.nix
index b434576..bf892d0 100644
--- a/Networks/raspberry_pi_rack.nix
+++ b/Networks/raspberry_pi_rack.nix
@@ -32,6 +32,19 @@
   pi-tri =
     { config, pkgs, lib, ... }:
 
+    {
+      # This value determines the NixOS release with which your system is to be
+      # compatible, in order to avoid breaking some software such as database
+      # servers. You should change this only after NixOS release notes say you
+      # should.
+      system.stateVersion = "19.09"; # Did you read the comment?
+      system.autoUpgrade.enable = true;
+      system.autoUpgrade.channel = https://nixos.org/channels/nixos-19.09;
+    };
+
+  pi-ceithir =
+    { config, pkgs, lib, ... }:
+
     {
       # This value determines the NixOS release with which your system is to be
       # compatible, in order to avoid breaking some software such as database