diff --git a/hive.nix b/hive.nix
index aee1fa0..73377fe 100644
--- a/hive.nix
+++ b/hive.nix
@@ -2,68 +2,57 @@ let
   mods = import ./modules;
   users = import ./users;
   sources = import ./npins;
-  inherit (import sources.nix-patches { patchFile = ./patches; }) mkNixpkgsSrc;
+  pkgs = import sources.nixpkgs-unstable { };
+  inherit (pkgs) lib;
+  inherit (lib)
+    mapAttrs
+    mapAttrs'
+    removeSuffix
+    evalModules
+    ;
 
-  unstable = {
-    nixpkgs = mkNixpkgsSrc {
-      src = sources.nixpkgs-unstable;
-      version = "unstable";
-    };
-    home-manager = "${sources.home-manager-unstable}/nixos";
-    nixvim = import sources.nixvim-unstable;
-  };
-  stable = {
-    nixpkgs = mkNixpkgsSrc {
-      src = sources.nixpkgs-stable;
-      version = "stable";
-    };
-    home-manager = "${sources.home-manager-stable}/nixos";
-    nixvim = import sources.nixvim-stable;
-  };
-  inherit (import unstable.nixpkgs { }) lib;
-
-  nodes = lib.mapAttrs' (name: _: {
-    name = lib.removeSuffix ".nix" name;
+  nodes = mapAttrs' (name: _: {
+    name = removeSuffix ".nix" name;
     value = import ./machines/${name};
   }) (builtins.readDir ./machines);
 
-  nodes-meta = lib.mapAttrs (_: n: n.meta) nodes;
+  meta' = evalModules {
+    modules = [
+      ./kat/meta.nix
+      { machines = mapAttrs (_: n: n.meta) nodes; }
+    ];
+    specialArgs = {
+      inherit pkgs sources;
+    };
+  };
+  meta = meta'.config // {
+    machines = mapAttrs (_: node: node.node_meta) meta'.config.machines;
+  };
 in
 {
-  meta = rec {
-    inherit (unstable) nixpkgs;
+  meta = {
+    nixpkgs = pkgs.path;
     specialArgs = {
-      inherit mods users sources;
-      meta = nodes-meta;
-      versions = {
-        inherit unstable stable;
-      };
+      inherit
+        mods
+        users
+        sources
+        meta
+        ;
+      kat-path = ./kat;
     };
-    nodeNixpkgs = lib.mapAttrs (
-      _: node:
-      lib.foldl (
-        pkgs: patch:
-        mkNixpkgsSrc {
-          src = pkgs;
-          version = patch;
-        }
-      ) (if node.unstable then unstable else stable).nixpkgs (node.nixPatches or [ ])
-    ) nodes-meta;
-    nodeSpecialArgs = lib.mapAttrs (name: node: {
-      inherit (node) unstable;
-      self-version = (if node.unstable then unstable else stable) // {
-        nixpkgs = nodeNixpkgs.${name};
-      };
-    }) nodes-meta;
+    nodeNixpkgs = mapAttrs (_: node: node.nixpkgs-paths.nixpkgs-src) meta.machines;
+    nodeSpecialArgs = mapAttrs (_: node: { self-meta = node; }) meta.machines;
   };
   defaults =
     {
       name,
+      kat-path,
       ...
     }:
     {
-      imports = [ ./kat ];
+      imports = [ kat-path ];
       networking.hostName = name;
     };
 }
-// lib.mapAttrs (_: n: n.config) nodes
+// mapAttrs (_: n: n.config) nodes
diff --git a/kat/default.nix b/kat/default.nix
index 916fcbc..1b6360c 100644
--- a/kat/default.nix
+++ b/kat/default.nix
@@ -3,7 +3,7 @@
   config,
   pkgs,
   sources,
-  self-version,
+  self-meta,
   ...
 }:
 with lib;
@@ -12,7 +12,7 @@ with lib;
     ./users
     ./proxies
     ./root.nix
-    self-version.home-manager
+    self-meta.home-manager
     "${sources.disko}/module.nix"
   ];
   options.kat = {
@@ -34,7 +34,6 @@ with lib;
     (mkIf config.kat.addArgs {
       _module.args = {
         ssh-keys = import ./ssh-keys { inherit lib; };
-        kat-path = ./.;
       };
     })
     {
@@ -61,10 +60,11 @@ with lib;
       };
       systemd.network.enable = true;
 
+      nixpkgs.overlays = map import self-meta.overlay-paths;
       nix = {
         nixPath = [
-          "nixpkgs=${builtins.storePath pkgs.path}"
-          "nixos=${builtins.storePath pkgs.path}"
+          "nixpkgs=${self-meta.nixpkgs-paths.nixpkgs}"
+          "nixos=${self-meta.nixpkgs-paths.nixpkgs}"
         ];
         channel.enable = false;
         settings.nix-path = config.nix.nixPath;
diff --git a/kat/meta.nix b/kat/meta.nix
new file mode 100644
index 0000000..6a8ccd7
--- /dev/null
+++ b/kat/meta.nix
@@ -0,0 +1,73 @@
+{
+  lib,
+  sources,
+  pkgs,
+  ...
+}:
+let
+  inherit (lib)
+    mkOption
+    concatStringsSep
+    ;
+  inherit (lib.types)
+    attrsOf
+    listOf
+    submodule
+    enum
+    path
+    unspecified
+    ;
+
+  machine_meta =
+    { config, ... }:
+    {
+      options = {
+        version = mkOption {
+          type = enum [
+            "stable"
+            "unstable"
+          ];
+        };
+        patches = mkOption {
+          type = listOf path;
+          default = [ ];
+        };
+        overlay-paths = mkOption {
+          type = listOf path;
+          default = [ ];
+          # /!\ Take care of imported files
+        };
+        node_meta = mkOption {
+          type = unspecified;
+          readOnly = true;
+        };
+      };
+      config.node_meta = rec {
+        inherit (config) version;
+        patches = [ ./nginx-fallback.patch ] ++ config.patches;
+        overlay-paths = [ "${sources.kat-pkgs}/overlay.nix" ] ++ config.overlay-paths;
+        nixpkgs-paths = {
+          nixpkgs-src = pkgs.applyPatches {
+            src = sources."nixpkgs-${version}";
+            name = "nixpkgs-${version}-patched";
+            inherit patches;
+          };
+          nixpkgs = pkgs.writeText "nixpkgs-entry.nix" ''
+            { overlays ? [ ], ... }@args:
+            import ${nixpkgs-paths.nixpkgs-src} (args // {
+              overlays = [
+                ${concatStringsSep "\n    " (map (p: "(import ${p})") overlay-paths)}
+              ] ++ overlays;
+            })
+          '';
+        };
+        home-manager = "${sources."home-manager-${version}"}/nixos";
+        nixvim = import sources."nixvim-${version}";
+      };
+    };
+in
+{
+  options.machines = mkOption {
+    type = attrsOf (submodule machine_meta);
+  };
+}
diff --git a/patches/nginx-fallback.patch b/kat/nginx-fallback.patch
similarity index 100%
rename from patches/nginx-fallback.patch
rename to kat/nginx-fallback.patch
diff --git a/kat/users/default.nix b/kat/users/default.nix
index 45ecfad..f471378 100644
--- a/kat/users/default.nix
+++ b/kat/users/default.nix
@@ -1,4 +1,4 @@
-{ config, pkgs, self-version, ... }:
+{ config, pkgs, self-meta, ... }:
 let
   zsh = import ./zsh.nix;
 in
@@ -9,7 +9,7 @@ in
       imports = [
         zsh.user
         ./neovim.nix
-        self-version.nixvim.homeManagerModules.nixvim
+        self-meta.nixvim.homeManagerModules.nixvim
       ];
       # options.kat = {
       #   ssh = mkEnableOption "ssh configuration";
diff --git a/machines/kat-betamail/default.nix b/machines/kat-betamail/default.nix
index 6b048bd..05d0435 100644
--- a/machines/kat-betamail/default.nix
+++ b/machines/kat-betamail/default.nix
@@ -1,7 +1,7 @@
 {
   meta = {
-    unstable = false;
-    pkgsPatches = [ "betamail" ];
+    version = "unstable";
+    patches = [ ./procmail_322.patch ];
   };
   config = import ./configuration.nix;
 }
diff --git a/patches/procmail_322.patch b/machines/kat-betamail/procmail_322.patch
similarity index 100%
rename from patches/procmail_322.patch
rename to machines/kat-betamail/procmail_322.patch
diff --git a/machines/kat-darknet/default.nix b/machines/kat-darknet/default.nix
index 66da70b..b1eb7c1 100644
--- a/machines/kat-darknet/default.nix
+++ b/machines/kat-darknet/default.nix
@@ -1,4 +1,4 @@
 {
-  meta.unstable = true;
+  meta.version = "unstable";
   config = import ./configuration.nix;
 }
diff --git a/machines/kat-degette/default.nix b/machines/kat-degette/default.nix
index e3d020b..23dfccf 100644
--- a/machines/kat-degette/default.nix
+++ b/machines/kat-degette/default.nix
@@ -1,4 +1,4 @@
 {
-  meta.unstable = false;
+  meta.version = "stable";
   config = import ./configuration.nix;
 }
diff --git a/machines/kat-iso.nix b/machines/kat-iso.nix
index 56b9068..891511e 100644
--- a/machines/kat-iso.nix
+++ b/machines/kat-iso.nix
@@ -1,5 +1,5 @@
 {
-  meta.unstable = true;
+  meta.version = "unstable";
   config =
     {
       pkgs,
diff --git a/machines/kat-kexec.nix b/machines/kat-kexec.nix
index 8fe1ac6..b4c4ef8 100644
--- a/machines/kat-kexec.nix
+++ b/machines/kat-kexec.nix
@@ -1,5 +1,5 @@
 {
-  meta.unstable = true;
+  meta.version = "unstable";
   config =
     {
       pkgs,
diff --git a/machines/kat-manah/default.nix b/machines/kat-manah/default.nix
index 66da70b..b1eb7c1 100644
--- a/machines/kat-manah/default.nix
+++ b/machines/kat-manah/default.nix
@@ -1,4 +1,4 @@
 {
-  meta.unstable = true;
+  meta.version = "unstable";
   config = import ./configuration.nix;
 }
diff --git a/machines/kat-orchid/configuration.nix b/machines/kat-orchid/configuration.nix
index 3f67f22..554cf81 100644
--- a/machines/kat-orchid/configuration.nix
+++ b/machines/kat-orchid/configuration.nix
@@ -5,7 +5,7 @@
   kat-path,
   ssh-keys,
   sources,
-  self-version,
+  self-meta,
   ...
 }:
 {
@@ -137,7 +137,7 @@
       localAddress = "192.168.123.2";
       autoStart = true;
       specialArgs = {
-        inherit kat-path ssh-keys sources self-version;
+        inherit kat-path ssh-keys sources self-meta;
       };
       config = {
         imports = [ kat-path ];
diff --git a/machines/kat-orchid/default.nix b/machines/kat-orchid/default.nix
index e3d020b..23dfccf 100644
--- a/machines/kat-orchid/default.nix
+++ b/machines/kat-orchid/default.nix
@@ -1,4 +1,4 @@
 {
-  meta.unstable = false;
+  meta.version = "stable";
   config = import ./configuration.nix;
 }
diff --git a/machines/kat-probook/default.nix b/machines/kat-probook/default.nix
index 66da70b..b1eb7c1 100644
--- a/machines/kat-probook/default.nix
+++ b/machines/kat-probook/default.nix
@@ -1,4 +1,4 @@
 {
-  meta.unstable = true;
+  meta.version = "unstable";
   config = import ./configuration.nix;
 }
diff --git a/machines/kat-son/default.nix b/machines/kat-son/default.nix
index 66da70b..b1eb7c1 100644
--- a/machines/kat-son/default.nix
+++ b/machines/kat-son/default.nix
@@ -1,4 +1,4 @@
 {
-  meta.unstable = true;
+  meta.version = "unstable";
   config = import ./configuration.nix;
 }
diff --git a/machines/kat-watcher/default.nix b/machines/kat-watcher/default.nix
index 66da70b..b1eb7c1 100644
--- a/machines/kat-watcher/default.nix
+++ b/machines/kat-watcher/default.nix
@@ -1,4 +1,4 @@
 {
-  meta.unstable = true;
+  meta.version = "unstable";
   config = import ./configuration.nix;
 }
diff --git a/machines/kat-www/default.nix b/machines/kat-www/default.nix
index e3d020b..23dfccf 100644
--- a/machines/kat-www/default.nix
+++ b/machines/kat-www/default.nix
@@ -1,4 +1,4 @@
 {
-  meta.unstable = false;
+  meta.version = "stable";
   config = import ./configuration.nix;
 }
diff --git a/npins/sources.json b/npins/sources.json
index a74b970..ac44e3f 100644
--- a/npins/sources.json
+++ b/npins/sources.json
@@ -39,19 +39,16 @@
       "url": "https://github.com/nix-community/home-manager/archive/65912bc6841cf420eb8c0a20e03df7cbbff5963f.tar.gz",
       "hash": "026hmc30kkyd9ihpjd6cm1b22galdi164ardhmj5x5jcszhjx4r9"
     },
-    "nix-patches": {
-      "type": "GitRelease",
+    "kat-pkgs": {
+      "type": "Git",
       "repository": {
         "type": "Git",
-        "url": "https://git.hubrecht.ovh/hubrecht/nix-patches"
+        "url": "https://git.dgnum.eu/lbailly/kat-pkgs.git"
       },
-      "pre_releases": false,
-      "version_upper_bound": null,
-      "release_prefix": null,
-      "version": "v0.5.0",
-      "revision": "e11ba20945f4a867f09d84343c37328288f274b4",
+      "branch": "master",
+      "revision": "6d804d5e17f7f6363fc300388b6cd6972810fc7c",
       "url": null,
-      "hash": "1c6cc44pwlg3ky6cnwhkml8ci77fw3sgjhwvqg0f6igxxf2fqv9v"
+      "hash": "1scfmdvm81b1ayi78k0kpg573vhxcvbzqvamzrs0g7xq5gv96imk"
     },
     "nixos-images": {
       "type": "Git",
diff --git a/patches/default.nix b/patches/default.nix
deleted file mode 100644
index 68dd6fe..0000000
--- a/patches/default.nix
+++ /dev/null
@@ -1,18 +0,0 @@
-let
-  general = [
-    {
-      _type = "static";
-      path = ./nginx-fallback.patch;
-    }
-  ];
-in
-{
-  unstable = general;
-  stable = general;
-  betamail = [
-    {
-      _type = "static";
-      path = ./procmail_322.patch;
-    }
-  ];
-}