diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 07a08ee5..83aa7050 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -1,19 +1,27 @@
+name: Build
+
 on:
   pull_request:
   push:
     branches: [develop]
 
+
 jobs:
-  lints:
-    name: Build
-    runs-on: ubuntu-22.04
+  os:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, macos-13]
+    name: OS
+    runs-on: ${{ matrix.os }}
     permissions:
       id-token: "write"
       contents: "read"
     steps:
-    - uses: actions/checkout@v4
-    - uses: DeterminateSystems/nix-installer-action@main
-    - uses: DeterminateSystems/magic-nix-cache-action@main
-    - uses: DeterminateSystems/flake-checker-action@main
-    # - name: Run `nix build`
-    #   run: nix build .
+      - uses: actions/checkout@v4
+      - uses: DeterminateSystems/nix-installer-action@v12
+      - uses: DeterminateSystems/magic-nix-cache-action@v7
+      - uses: DeterminateSystems/flake-checker-action@v8
+      - run: |
+          nix build .#build-os-configurations
+          ls -lha result/
diff --git a/flake.lock b/flake.lock
index 87984e11..ce63ecfa 100644
--- a/flake.lock
+++ b/flake.lock
@@ -254,11 +254,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1692613703,
-        "narHash": "sha256-ByFRYQ8J4YSeAU6N0gUc5nmIjAGoiDU+jMUL73Ns0ZU=",
+        "lastModified": 1715935620,
+        "narHash": "sha256-b60zHhqS67LW9nTxl7p6ba2OdXJAMoMclEYHbRPpwKM=",
         "owner": "steveeJ-forks",
         "repo": "nix-darwin",
-        "rev": "72d647c8bda6d8d8a88ba2b63b56ce4e0be57ea7",
+        "rev": "9f51e374d7cc7fdf7c9b2578a5757b92d028e2ea",
         "type": "github"
       },
       "original": {
@@ -679,7 +679,7 @@
         "versions": "versions"
       },
       "locked": {
-        "narHash": "sha256-eczsmDRDhXlN6GQ5h0UBWsDe5hKnthl//O3hiC1+JnY=",
+        "narHash": "sha256-EwKzTn3/LhIFtaflp4X96RUcAIyJKzftSfUM+vz6wCk=",
         "type": "tarball",
         "url": "https://hydra.holo.host/channel/custom/holo-nixpkgs/2112/holo-nixpkgs/nixexprs.tar.xz"
       },
@@ -947,7 +947,7 @@
     "keys_thetasinner": {
       "flake": false,
       "locked": {
-        "narHash": "sha256-8RWZCPJpXCWx9vwVoimLJG0YQzXow9bexgUnyb9T5Hs=",
+        "narHash": "sha256-sDa25rA0Qb8ASDLWBXQ3YIDVwDoK56cgQGow+3aWNfE=",
         "type": "file",
         "url": "https://github.com/ThetaSinner.keys"
       },
@@ -1305,6 +1305,22 @@
         "type": "github"
       }
     },
+    "nixpkgs-24-05": {
+      "locked": {
+        "lastModified": 1718086528,
+        "narHash": "sha256-hoB7B7oPgypePz16cKWawPfhVvMSXj4G/qLsfFuhFjw=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "47b604b07d1e8146d5398b42d3306fdebd343986",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-24.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nixpkgs-lib": {
       "locked": {
         "dir": "lib",
@@ -1439,22 +1455,6 @@
         "type": "github"
       }
     },
-    "nixpkgsNix": {
-      "locked": {
-        "lastModified": 1715787315,
-        "narHash": "sha256-cYApT0NXJfqBkKcci7D9Kr4CBYZKOQKDYA23q8XNuWg=",
-        "owner": "nixos",
-        "repo": "nixpkgs",
-        "rev": "33d1e753c82ffc557b4a585c77de43d4c922ebb5",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nixos",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "nixpkgsPulumi": {
       "locked": {
         "lastModified": 1715674170,
@@ -1683,9 +1683,12 @@
           "nixpkgs-23-11"
         ],
         "nixpkgs-23-11": "nixpkgs-23-11",
+        "nixpkgs-24-05": "nixpkgs-24-05",
         "nixpkgsGithubActionRunners": "nixpkgsGithubActionRunners",
         "nixpkgsMaster": "nixpkgsMaster",
-        "nixpkgsNix": "nixpkgsNix",
+        "nixpkgsNix": [
+          "nixpkgs-24-05"
+        ],
         "nixpkgsPulumi": "nixpkgsPulumi",
         "nixpkgsUnstable": "nixpkgsUnstable",
         "sbd": "sbd",
diff --git a/flake.nix b/flake.nix
index 81326255..c8f2f344 100644
--- a/flake.nix
+++ b/flake.nix
@@ -4,7 +4,8 @@
   inputs = {
     nixpkgs.follows = "nixpkgs-23-11";
     nixpkgs-23-11 = {url = "github:nixos/nixpkgs/nixos-23.11";};
-    nixpkgsNix = {url = "github:nixos/nixpkgs/nixos-unstable";};
+    nixpkgs-24-05 = {url = "github:nixos/nixpkgs/nixos-24.05";};
+    nixpkgsNix.follows = "nixpkgs-24-05";
     nixpkgsGithubActionRunners = {url = "github:nixos/nixpkgs/nixos-unstable";};
     nixpkgsUnstable = {url = "github:nixos/nixpkgs/nixos-unstable";};
     nixpkgsMaster = {url = "github:nixos/nixpkgs/master";};
@@ -135,6 +136,7 @@
         inputs',
         pkgs,
         lib,
+        system,
         ...
       }: {
         # Per-system attributes can be defined here. The self' and inputs'
@@ -221,11 +223,49 @@
             '';
           };
 
-        packages = {
-          nomad = inputs'.nixpkgs.legacyPackages.nomad_1_6;
-
-          nixos-anywhere = inputs'.nixos-anywhere.packages.default;
-        };
+        packages =
+          {
+            # nomad = pkgs.nomad_1_6;
+
+            nixos-anywhere = inputs'.nixos-anywhere.packages.default;
+          }
+          // (
+            let
+              mkOsConfigCheck = osConfigs: let
+                filteredBySystem =
+                  lib.filterAttrs (
+                    key: value:
+                      (value.pkgs.system == system)
+                      # needs private repos
+                      && (key != "tfgrid-hpos")
+                  )
+                  osConfigs;
+                asStrings =
+                  lib.mapAttrsToList (
+                    key: value:
+                      builtins.trace "evaluating ${key} (${value.pkgs.system})..."
+                      "ln -s ${value.config.system.build.toplevel} $out/${key}"
+                  )
+                  filteredBySystem;
+              in
+                pkgs.stdenv.mkDerivation {
+                  name = "check-osconfigurations";
+                  phases = "installPhase";
+                  installPhase = "mkdir $out;" + builtins.concatStringsSep "\n" asStrings;
+                };
+            in {
+              build-os-configurations =
+                if pkgs.stdenv.isLinux
+                then
+                  mkOsConfigCheck (builtins.removeAttrs self.nixosConfigurations [
+                    # too big for current CI structure and rarely used
+                    "vm-nixcache"
+                  ])
+                else if pkgs.stdenv.isDarwin
+                then mkOsConfigCheck self.darwinConfigurations
+                else throw "unexpected case";
+            }
+          );
       };
       flake = {
         # The usual flake attributes can be defined here, including system-
diff --git a/modules/nixos/kitsune-bootstrap.nix b/modules/nixos/kitsune-bootstrap.nix
index 9b06429c..59906c98 100644
--- a/modules/nixos/kitsune-bootstrap.nix
+++ b/modules/nixos/kitsune-bootstrap.nix
@@ -11,7 +11,7 @@ in {
     enable = lib.mkEnableOption "kitsune-bootstrap";
 
     package = lib.mkOption {
-      default = self.inputs.holochain.packages.${pkgs.system}.holochain;
+      default = self.inputs.holochain.packages.${pkgs.system}.holochain.override {cargoExtraArgs = " --bin kitsune-bootstrap";};
       type = lib.types.package;
     };
 
diff --git a/modules/nixos/shared.nix b/modules/nixos/shared.nix
index 25d1d2b9..2e9cc640 100644
--- a/modules/nixos/shared.nix
+++ b/modules/nixos/shared.nix
@@ -17,7 +17,7 @@
     # ]
     ;
 
-  nix.package = lib.mkDefault inputs.nixpkgsNix.legacyPackages.${pkgs.stdenv.system}.nixVersions.nix_2_20;
+  nix.package = lib.mkDefault inputs.nixpkgsNix.legacyPackages.${pkgs.stdenv.system}.nixVersions.nix_2_21;
 
   nix.settings.extra-platforms =
     lib.mkIf pkgs.stdenv.isDarwin ["x86_64-darwin" "aarch64-darwin"];