diff --git a/pkgs/tools/package-management/nix/unstable.nix b/pkgs/tools/package-management/nix/unstable.nix
index 6bd428a2612a..24ab50d12542 100644
--- a/pkgs/tools/package-management/nix/unstable.nix
+++ b/pkgs/tools/package-management/nix/unstable.nix
@@ -4,11 +4,11 @@
 }:
 
 stdenv.mkDerivation {
-  name = "nix-0.11pre8456";
+  name = "nix-0.11pre8648";
   
   src = fetchurl {
-    url = http://nix.cs.uu.nl/dist/nix/nix-0.11pre8456/nix-0.11pre8456.tar.bz2;
-    md5 = "7c6939f94f2a5fe8586df3d39b0e1ab5";
+    url = http://nix.cs.uu.nl/dist/nix/nix-0.11pre8648/nix-0.11pre8648.tar.bz2;
+    md5 = "f3994bff46a9960e9d085ab5e924f8c5";
   };
   
   buildInputs = [perl curl openssl];