1error:2 … while evaluating a branch condition3 at «string»:25:5:4 24| v:5 25| if !builtins.isAttrs v || isDrv v then6 | ^7 26| v89 … in the left operand of the OR (||) operator10 at «string»:25:28:11 24| v:12 25| if !builtins.isAttrs v || isDrv v then13 | ^14 26| v1516 … while evaluating definitions from `/nix/store/lrxvs4l9bqbgjfz7w9bkfg5zqq442jxc-source/modules/transposition.nix':1718 … while evaluating definitions from `/nix/store/lxr5ikw064z3rysi7icw37sc80c0vhgi-source/flake.nix, via option perSystem':1920 … while evaluating definitions from `/nix/store/lrxvs4l9bqbgjfz7w9bkfg5zqq442jxc-source/modules/transposition.nix':2122 … while evaluating definitions from `/nix/store/lxr5ikw064z3rysi7icw37sc80c0vhgi-source/nix/packages/flake-module.nix, via option perSystem':2324 … while evaluating the module argument `pkgs' in ":anon-13:anon-1":2526 … noting that argument `pkgs` is not externally provided, so querying `_module.args` instead, requiring `config`2728 … while evaluating definitions from `/nix/store/lxr5ikw064z3rysi7icw37sc80c0vhgi-source/flake.nix, via option perSystem':2930 (stack trace truncated; use '--show-trace' to show the full, detailed trace)3132 error: Nixpkgs 26.11 has dropped support for x86_64-darwin.3334 The 26.05 stable branch still supports x86_64-darwin, and will35 receive security fixes until the end of 2026. If you use channels,36 you can switch to 26.05 as follows:3738 $ sudo nix-channel --add https://nixos.org/channels/nixpkgs-26.05-darwin nixpkgs39 $ sudo nix-channel --update4041 If this doesn’t work, you may need to run:4243 # Lack of sudo is deliberate:44 $ nix-channel --remove nixpkgs4546 If you use flakes, switch your flake input:4748 inputs.nixpkgs = {49 url = "github:NixOS/nixpkgs/nixpkgs-26.05-darwin";50 };5152 See the release notes for more information and alternatives:5354 https://nixos.org/manual/nixpkgs/unstable/release-notes#x86_64-darwin-26.11