diff --git a/default.nix b/default.nix
index 05753d944d6b6285c319469805cd8ad806f7341a..14551fd229da8ad69c02e9de84d586c9324eb797 100644
--- a/default.nix
+++ b/default.nix
@@ -1,16 +1,15 @@
 let
-  pkgs = import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/18.03.tar.gz") {};
   kapack = import
     ( fetchTarball "https://github.com/oar-team/kapack/archive/master.tar.gz")
-  { inherit pkgs; };
+  { };
 in
 
 with kapack;
-with pkgs;
 
 (batsched_dev.override {}).overrideAttrs (attrs: rec {
     name = "batsched-1.4.0-nix-local";
     src = ../.;
     enableParallelBuilding = true;
     doCheck = false;
+    dontStrip = true;
 })