diff --git a/pkgs/tools/package-management/nix/unstable.nix b/pkgs/tools/package-management/nix/unstable.nix
index 912248b694c3..4442deb36bcd 100644
--- a/pkgs/tools/package-management/nix/unstable.nix
+++ b/pkgs/tools/package-management/nix/unstable.nix
@@ -5,11 +5,11 @@
 }:
 
 stdenv.mkDerivation rec {
-  name = "nix-1.0pre2668_46cdc6a";
+  name = "nix-1.1pre2714_2f3f413";
 
   src = fetchurl {
-    url = "http://hydra.nixos.org/build/2492261/download/4/${name}.tar.bz2";
-    sha256 = "d9a1cfbee1670bc700593d81211c47eb8d7623aa9699d18a414ecaddccabfa1a";
+    url = "http://hydra.nixos.org/build/2724747/download/4/${name}.tar.bz2";
+    sha256 = "ec026709405dfcbff387418c007915711312ac574c046c38798990666bd339a6";
   };
 
   buildNativeInputs = [ perl pkgconfig ];
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 71a961480ef0..4328c7c7d367 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -8422,14 +8422,10 @@ let
     stateDir = getConfig [ "nix" "stateDir" ] "/nix/var";
   };
 
-  /*
   nixUnstable = callPackage ../tools/package-management/nix/unstable.nix {
     storeDir = getConfig [ "nix" "storeDir" ] "/nix/store";
     stateDir = getConfig [ "nix" "stateDir" ] "/nix/var";
   };
-  */
-
-  nixUnstable = nixStable;
 
   nixCustomFun = src: preConfigure: enableScripts: configureFlags:
     import ../tools/package-management/nix/custom.nix {