diff --git a/flake.lock b/flake.lock
index 4b4f0076..966431f9 100644
--- a/flake.lock
+++ b/flake.lock
@@ -42,47 +42,32 @@
         "nixpkgs-regression": "nixpkgs-regression"
       },
       "locked": {
-        "lastModified": 1707750141,
-        "narHash": "sha256-9qSzGQs/Rjf2i3UQjyaZUznZzYDHkLYro/1FTT1easg=",
+        "lastModified": 1712849398,
+        "narHash": "sha256-10z/SoidVl9/lh56cMLj7ntJZHtVrumFvmn1YEqXmaM=",
         "owner": "NixOS",
         "repo": "nix",
-        "rev": "c4ebb82da4eade975e874da600dc50e9dec610cb",
+        "rev": "60824fa97c588a0faf68ea61260a47e388b0a4e5",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
+        "ref": "2.21-maintenance",
         "repo": "nix",
         "type": "github"
       }
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1705033721,
-        "narHash": "sha256-K5eJHmL1/kev6WuqyqqbS1cdNnSidIZ3jeqJ7GbrYnQ=",
+        "lastModified": 1712848736,
+        "narHash": "sha256-CzZwhqyLlebljv1zFS2KWVH/3byHND0LfaO1jKsGuVo=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "a1982c92d8980a0114372973cbdfe0a307f1bdea",
+        "rev": "1d6a23f11e44d0fb64b3237569b87658a9eb5643",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixos-23.05-small",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs-for-fileset": {
-      "locked": {
-        "lastModified": 1706098335,
-        "narHash": "sha256-r3dWjT8P9/Ah5m5ul4WqIWD8muj5F+/gbCdjiNVBKmU=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "a77ab169a83a4175169d78684ddd2e54486ac651",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-23.11",
+        "ref": "nixos-23.11-small",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -106,8 +91,7 @@
     "root": {
       "inputs": {
         "nix": "nix",
-        "nixpkgs": "nixpkgs",
-        "nixpkgs-for-fileset": "nixpkgs-for-fileset"
+        "nixpkgs": "nixpkgs"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 4dc7d25e..fd6ad586 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,16 +1,11 @@
 {
   description = "A Nix-based continuous build system";
 
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05-small";
-  inputs.nix.url = "github:NixOS/nix";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11-small";
+  inputs.nix.url = "github:NixOS/nix/2.21-maintenance";
   inputs.nix.inputs.nixpkgs.follows = "nixpkgs";
 
-  # TODO get rid of this once https://github.com/NixOS/nix/pull/9546 is
-  # mered and we upgrade or Nix, so the main `nixpkgs` input is at least
-  # 23.11 and has `lib.fileset`.
-  inputs.nixpkgs-for-fileset.url = "github:NixOS/nixpkgs/nixos-23.11";
-
-  outputs = { self, nixpkgs, nix, nixpkgs-for-fileset }:
+  outputs = { self, nixpkgs, nix }:
     let
       systems = [ "x86_64-linux" "aarch64-linux" ];
       forEachSystem = nixpkgs.lib.genAttrs systems;
@@ -67,7 +62,7 @@
         };
 
         hydra = final.callPackage ./package.nix {
-          inherit (nixpkgs-for-fileset.lib) fileset;
+          inherit (nixpkgs.lib) fileset;
           rawSrc = self;
         };
       };