diff --git a/flake.lock b/flake.lock
index 8cf6324..801b479 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,18 +2,17 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1700907157,
-        "narHash": "sha256-n71E17bx1cpSDJOxcB3G9UxjUUIzsIvdyY2oWAiiKv4=",
-        "owner": "natsukium",
+        "lastModified": 1707347730,
+        "narHash": "sha256-0etC/exQIaqC9vliKhc3eZE2Mm2wgLa0tj93ZF/egvM=",
+        "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "483af9297efc85e6bf0c7045cc07b685e31ca6a8",
+        "rev": "6832d0d99649db3d65a0e15fa51471537b2c56a6",
         "type": "github"
       },
       "original": {
-        "owner": "natsukium",
-        "ref": "pydantic2",
-        "repo": "nixpkgs",
-        "type": "github"
+        "id": "nixpkgs",
+        "ref": "nixos-23.11",
+        "type": "indirect"
       }
     },
     "root": {
diff --git a/flake.nix b/flake.nix
index 85f223f..2b041bc 100644
--- a/flake.nix
+++ b/flake.nix
@@ -3,8 +3,8 @@
 
   inputs = {
     nixpkgs = {
-      # url = "nixpkgs/nixos-23.05";
-      url = "github:natsukium/nixpkgs/pydantic2";
+      url = "nixpkgs/nixos-23.11";
+      # url = "github:natsukium/nixpkgs/pydantic2";
     };
   };
 
@@ -19,21 +19,21 @@
     py = pkgs.python3.override {
       packageOverrides = final: prev: {
         django = prev.django_4;
-        cronsim = let
-          version = "2.5";
-          pname = "cronsim";
-          src = pkgs.fetchPypi {
-            inherit pname version;
-            hash = "sha256-FTzwIZ3MGgyp5xqDav22B5ZTfYxSHGhsenMTSDdXM78=";
-          };
-        in
-          prev.buildPythonPackage {
-            inherit pname version src;
-            # nativeCheckInputs = [ prev.pytestCheckHook ];
-            pythonImportsCheck = [
-              "cronsim"
-            ];
-          };
+        # cronsim = let
+        #   version = "2.5";
+        #   pname = "cronsim";
+        #   src = pkgs.fetchPypi {
+        #     inherit pname version;
+        #     hash = "sha256-FTzwIZ3MGgyp5xqDav22B5ZTfYxSHGhsenMTSDdXM78=";
+        #   };
+        # in
+        #   prev.buildPythonPackage {
+        #     inherit pname version src;
+        #     # nativeCheckInputs = [ prev.pytestCheckHook ];
+        #     pythonImportsCheck = [
+        #       "cronsim"
+        #     ];
+        #   };
       };
     };
     baseImage = {
@@ -60,10 +60,61 @@
     };
   in {
     packages.${system} = {
+      oncalendar = let
+      in
+        py.pkgs.buildPythonApplication {
+          inherit pname version propagatedBuildInputs;
+          format = "other";
+
+          outputs = ["out" "static" "doc"];
+
+          src = pkgs.fetchFromGitHub {
+            owner = "healthchecks";
+            repo = pname;
+            rev = "v${version}";
+            inherit hash;
+          };
+
+          dontPatch = true;
+          dontConfigure = true;
+          dontBuild = true;
+          doCheck = false;
+
+          installPhase = ''
+            mkdir -p $out/app
+            cp -r CHANGELOG.md hc manage.py templates $out/app
+            chmod +x $out/app/manage.py
+
+            mkdir -p $doc
+            cp -r *.md LICENSE $doc
+
+            mkdir -p $static
+            DEBUG=False SECRET_KEY=build-key STATIC_ROOT=$static ${py}/bin/python ./manage.py collectstatic --noinput
+            DEBUG=False SECRET_KEY=build-key STATIC_ROOT=$static ${py}/bin/python ./manage.py compress
+            cp -r static-collected/* $static
+
+            cp ${localSettings} $out/app/hc/local_settings.py
+          '';
+
+          passthru = {
+            # PYTHONPATH of all dependencies used by the package
+            pythonPath = py.pkgs.makePythonPath propagatedBuildInputs;
+
+            tests = {
+              inherit (pkgs.nixosTests) healthchecks;
+            };
+          };
+
+          meta = with pkgs.lib; {
+            homepage = "https://github.com/healthchecks/healthchecks";
+            description = "A cron monitoring tool written in Python & Django ";
+            license = licenses.bsd3;
+          };
+        };
       healthchecks = let
         pname = "healthchecks";
-        version = "3.0.1";
-        hash = "sha256-r8wzIZPetnTEJDKPx/Oxk+gzs8gbjEHSi40LSxLb1Js=";
+        version = "3.2";
+        hash = "sha256-TAhr1PeoGp/zqsnJz9C/w7auip4RdRIFSxvo6haOG0Q=";
         localSettings = pkgs.writeText "local_settings.py" ''
           import os
           CSRF_TRUSTED_HOSTS = os.getenv("CSRF_TRUSTED_HOSTS", "").split(",")