diff --git a/configuration.nix b/configuration.nix
index e2cbe6c..045ba9a 100644
--- a/configuration.nix
+++ b/configuration.nix
@@ -22,6 +22,10 @@
   # 2. Matrix Synapse migration (https://matrix-org.github.io/synapse/latest/upgrade.html)
   system.stateVersion = "23.05";
 
+  nixpkgs.source = builtins.fetchTarball
+    { url = "https://github.com/NixOS/nixpkgs/archive/66c7fa70cd1a.tar.gz";
+      sha256 = "12a69mm612h2yxqkmak06km38hnxijnj6n76lrcl235j8c8zf8y0";
+    };
 
   boot.kernelPackages = pkgs.linuxPackages_latest;
   boot.tmp.useTmpfs = true;
diff --git a/custom/default.nix b/custom/default.nix
index 406ad59..5763116 100644
--- a/custom/default.nix
+++ b/custom/default.nix
@@ -10,6 +10,9 @@
 
       # Safely handle secrets
       ./modules/secrets-store.nix
+
+      # Pin Nixpkgs
+      ./modules/nixpkgs.nix
     ];
 
 }
diff --git a/custom/modules/nixpkgs.nix b/custom/modules/nixpkgs.nix
new file mode 100644
index 0000000..d40c7d5
--- /dev/null
+++ b/custom/modules/nixpkgs.nix
@@ -0,0 +1,39 @@
+{ config, lib, ... }:
+
+let
+  nixpkgs = config.nixpkgs.source;
+
+  conf = "${toString ../..}/configuration.nix";
+
+  rebuild = self: super:
+    { nixos-rebuild = super.nixos-rebuild.overrideAttrs (old:
+      { postInstall = old.postInstall +
+        ''
+          sed -i "$target" \
+            -e '/^export PATH/ a \
+              export NIX_PATH="nixpkgs=${nixpkgs}:nixos-config=${conf}"' \
+            -e 's/remoteSudo=/remoteSudo=1/' \
+            -e 's/-A system/-A system --no-out-link/'
+        '';
+      });
+    };
+
+in
+
+{
+
+  options.nixpkgs.source = lib.mkOption
+    { type = lib.types.path;
+      description = "Nixpkgs sources";
+    };
+
+  config =
+    { nixpkgs.pkgs = import nixpkgs { overlays = [ rebuild ]; };
+      nix.nixPath =
+        [ "nixpkgs=/run/current-system/nixpkgs"
+          "nixos-config=${conf}"
+        ];
+      system.extraSystemBuilderCmds = "ln -s ${nixpkgs} $out/nixpkgs";
+    };
+
+}
diff --git a/email.nix b/email.nix
index d55f0e8..d7a49af 100644
--- a/email.nix
+++ b/email.nix
@@ -3,8 +3,8 @@
 {
   imports = [
     (builtins.fetchTarball {
-      url = "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/nixos-23.05/nixos-mailserver-nixos-23.05.tar.gz";
-      sha256 = "1ngil2shzkf61qxiqw11awyl81cr7ks2kv3r3k243zz7v2xakm5c";
+      url = "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver/-/archive/nixos-24.05/nixos-mailserver-nixos-24.05.tar.gz";
+      sha256 = "0clvw4622mqzk1aqw1qn6shl9pai097q62mq1ibzscnjayhp278b";
     })
   ];
 
diff --git a/jobs.nix b/jobs.nix
index fbf6c20..6073223 100644
--- a/jobs.nix
+++ b/jobs.nix
@@ -17,6 +17,7 @@ with lib;
 
   systemd.services.ydns = {
     description = "update ydns address record";
+    wants    = [ "network-online.target" ];
     after    = [ "network-online.target" ];
     startAt  = "*:0/30";
 
diff --git a/neovim.nix b/neovim.nix
index 360dfb2..a1c9aa9 100644
--- a/neovim.nix
+++ b/neovim.nix
@@ -19,9 +19,9 @@ let
       nix-queries fortran-queries
       (nvim-treesitter.withPlugins (p: with p;
         [ bash fish
-          fortran haskell
+          c haskell
           html css markdown
-          nix python
+          nix python lua
         ]))
 
       # Misc
@@ -140,6 +140,7 @@ let
     opt.foldmethod = "expr"                       -- Folding
     opt.foldexpr   = 'nvim_treesitter#foldexpr()' --
     opt.foldlevel  = 99                           -- open by default
+    opt.foldopen:remove("search")                 -- don't open when searching
 
     --
     -- OSC 52 clipboard
diff --git a/packages.nix b/packages.nix
index b1e9910..08a87cd 100644
--- a/packages.nix
+++ b/packages.nix
@@ -8,6 +8,12 @@
           roomId     = "!FsUSHSNMPMVTFFcvJo:maxwell.ydns.eu";
           authToken  = config.secrets.passwords.matrix;
         };
+
+      haskellPackages = super.haskellPackages.extend (hself: hsuper:
+        { breve =  hself.callCabal2nix "breve" (builtins.fetchTarball
+          { url = "https://hackage.haskell.org/package/breve-0.5.1.0/breve-0.5.1.0.tar.gz";
+          }) {};
+        });
     });
 
   environment.systemPackages = with pkgs; [