error: … while evaluating a branch condition at «string»:25:5: 24| v: 25| if !builtins.isAttrs v || isDrv v then | ^ 26| v … in the left operand of the OR (||) operator at «string»:25:28: 24| v: 25| if !builtins.isAttrs v || isDrv v then | ^ 26| v (stack trace truncated; use '--show-trace' to show the full, detailed trace) error: Nixpkgs 26.11 has dropped support for x86_64-darwin. The 26.05 stable branch still supports x86_64-darwin, and will receive security fixes until the end of 2026. If you use channels, you can switch to 26.05 as follows: $ sudo nix-channel --add https://nixos.org/channels/nixpkgs-26.05-darwin nixpkgs $ sudo nix-channel --update If this doesn’t work, you may need to run: # Lack of sudo is deliberate: $ nix-channel --remove nixpkgs If you use flakes, switch your flake input: inputs.nixpkgs = { url = "github:NixOS/nixpkgs/nixpkgs-26.05-darwin"; }; See the release notes for more information and alternatives: https://nixos.org/manual/nixpkgs/unstable/release-notes#x86_64-darwin-26.11