diff --git a/fixtures/example/package.nix b/fixtures/example/package.nix
index 8ab2e79..183f61e 100644
--- a/fixtures/example/package.nix
+++ b/fixtures/example/package.nix
@@ -5,7 +5,7 @@
 let
   src = ./.;
 
-  beamPackages = pkgs.beamMinimal28Packages.extend (_: prev: { elixir = prev.elixir_1_19; });
+  beamPackages = pkgs.beamMinimal28Packages.overrideScope (_: prev: { elixir = prev.elixir_1_19; });
 
   mixNixDeps = pkgs.callPackages ./deps.nix {
     beamPackages = beamPackages;
diff --git a/flake.lock b/flake.lock
index bbcfda6..1ffdc78 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1782118813,
-        "narHash": "sha256-BnbXO5s5EhV89lLXMAGCzPdEN5a6vNqvMk71obeTEUw=",
+        "lastModified": 1787394516,
+        "narHash": "sha256-pRGOQSClnXNI2iLUG6DYpsGvYcuw0drOutVZFTJNw90=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "b3c092d3c36d91e2f61f3dfb39a159f180a56659",
+        "rev": "c8f90650c15282fa8656a041bfbbd2403997a9a7",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index b22fd84..774284e 100644
--- a/flake.nix
+++ b/flake.nix
@@ -27,7 +27,7 @@
       devShells = forAllSystems (
         { pkgs, ... }:
         let
-          beamPackages = pkgs.beam29Packages.extend (_: prev: { elixir = prev.elixir_1_20; });
+          beamPackages = pkgs.beam29Packages.overrideScope (_: prev: { elixir = prev.elixir_1_20; });
         in
         {
           default = pkgs.callPackage ./shells/local.nix { inherit beamPackages; };