diff --git a/cluster/nix/modules/kubernetes.nix b/cluster/nix/modules/kubernetes.nix
index 59e8b4ff..10560cd9 100644
--- a/cluster/nix/modules/kubernetes.nix
+++ b/cluster/nix/modules/kubernetes.nix
@@ -4,17 +4,17 @@ with (( import ../defs-cluster-k0.nix ) config.networking.hostName);
 let
   # Pin for k8s packages. This is so that upagrading the system will not upgrade the k8s control or data planes.
   k8spkgs = import (fetchGit {
-    # Now at 1.14.3
-    name = "nixos-unstable-2019-06-17";
+    # Now at 1.15.4
+    name = "nixos-unstable-2019-09-18";
     url = https://github.com/nixos/nixpkgs-channels/;
-    rev = "415e8e5820b7825fb74a6c7986bf6af725227eaa";
+    rev = "b21a3356f01b59992432a907f17e66abc77f17a0";
   }) {};
   # Pin for kubelet
   k8spkgsKubelet = import (fetchGit {
-    # Now at 1.14.3
-    name = "nixos-unstable-2019-06-17";
+    # Now at 1.15.4
+    name = "nixos-unstable-2019-09-18";
     url = https://github.com/nixos/nixpkgs-channels/;
-    rev = "415e8e5820b7825fb74a6c7986bf6af725227eaa";
+    rev = "b21a3356f01b59992432a907f17e66abc77f17a0";
   }) {};
 
 in rec {