diff --git a/flake.lock b/flake.lock
index 94e0bfb..9602bc7 100644
--- a/flake.lock
+++ b/flake.lock
@@ -16,9 +16,26 @@
         "type": "github"
       }
     },
+    "nixpkgs-stable": {
+      "locked": {
+        "lastModified": 1779102034,
+        "narHash": "sha256-vZJZjLo513IeI8hjzHFc6TDezUd4uCE2Eq4SNO3DNNg=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "687f05a9184cad4eaf905c48b63649e3a86f5433",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-25.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-stable": "nixpkgs-stable"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 3b729fe..60ab314 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,12 +2,14 @@
   description = "DLSite download organizer";
 
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  inputs.nixpkgs-stable.url = "github:NixOS/nixpkgs/nixos-25.11";
 
-  outputs = { self, nixpkgs }: let
+  outputs = { self, nixpkgs, nixpkgs-stable }: let
     pkgs = import nixpkgs {
       system = "x86_64-linux";
       config.allowUnfree = true;
     };
+    pkgs-stable = import nixpkgs-stable { system = "x86_64-linux"; };
     project = builtins.fromTOML (builtins.readFile ./pyproject.toml);
   in {
     packages.x86_64-linux = with pkgs.python3Packages; rec {
@@ -19,7 +21,7 @@
           sha256 = "sha256-K7xbHtz2SF8Rs+2Rm0Llw5jWnqlTLP5vSuAM3mXEAeY=";
         };
         pyproject = true;
-        nativeBuildInputs = [ pkgs.pdm ];
+        nativeBuildInputs = [ (assert pkgs.pdm.version == "2.26.6"; pkgs-stable.pdm) ];
         propagatedBuildInputs = [
           lxml
           aiohttp