diff --git a/pkgs/development/tools/misc/hydra/default.nix b/pkgs/development/tools/misc/hydra/default.nix
index a124b4a5c6e..ac5600519b4 100644
--- a/pkgs/development/tools/misc/hydra/default.nix
+++ b/pkgs/development/tools/misc/hydra/default.nix
@@ -2,12 +2,12 @@
 
 {
   hydra-unstable = callPackage ./common.nix {
-    version = "2021-05-03";
+    version = "2021-08-11";
     src = fetchFromGitHub {
       owner = "NixOS";
       repo = "hydra";
-      rev = "886e6f85e45a1f757e9b77d2a9e4539fbde29468";
-      sha256 = "t7Qb57Xjc0Ou+VDGC1N5u9AmeODW6MVOwKSrYRJq5f0=";
+      rev = "9bce425c3304173548d8e822029644bb51d35263";
+      sha256 = "sha256-tGzwKNW/odtAYcazWA9bPVSmVXMGKfXsqCA1UYaaxmU=";
     };
     nix = nixUnstable;
 
diff --git a/pkgs/tools/package-management/nix/default.nix b/pkgs/tools/package-management/nix/default.nix
index bc743a3c54e..f9a476f6be6 100644
--- a/pkgs/tools/package-management/nix/default.nix
+++ b/pkgs/tools/package-management/nix/default.nix
@@ -228,13 +228,13 @@ in rec {
   nixUnstable = lib.lowPrio (callPackage common rec {
     pname = "nix";
     version = "2.4${suffix}";
-    suffix = "pre20210707_02dd6bb";
+    suffix = "pre20210802_47e96bb";
 
     src = fetchFromGitHub {
       owner = "NixOS";
       repo = "nix";
-      rev = "02dd6bb610e55a009cd7a4c83639698d3a7acaa2";
-      sha256 = "sha256-ARRiLrDOK+JQtvVXsYegspENYimQzilvdTfO7eiBuaA=";
+      rev = "47e96bb533f8cacc171bec9b688b134de31a48a9";
+      sha256 = "sha256-vwj1fAGn3Pl9Vr/qSL+oDxuwbRzEdI3dsEg6o3xTmWg=";
     };
 
     boehmgc = boehmgc_nixUnstable;