1error:2 … while evaluating the attribute 'optionalValue.value'3 at «github:nix-community/nixpkgs.lib/db3f255737b94216eb71cce308e2912cf6bc2d7c?narHash=sha256-ePjCwr1sNm9NYUqywL7QfK3JnlS015msC%2BeBu2zKlp8%3D»/lib/modules.nix:1310:5:4 1309|5 1310| optionalValue = if isDefined then { value = mergedValue; } else { };6 | ^7 1311| };89 … while evaluating a branch condition10 at «github:nix-community/nixpkgs.lib/db3f255737b94216eb71cce308e2912cf6bc2d7c?narHash=sha256-ePjCwr1sNm9NYUqywL7QfK3JnlS015msC%2BeBu2zKlp8%3D»/lib/modules.nix:1310:21:11 1309|12 1310| optionalValue = if isDefined then { value = mergedValue; } else { };13 | ^14 1311| };1516 … while evaluating definitions from `/nix/store/xfg4bws749i95jvnxhymxmfwailzk38q-source/modules/transposition.nix':1718 … while evaluating definitions from `/nix/store/jr5h96invxdyvkgpm2fr27axlha4zmry-source/flake.nix, via option perSystem':1920 … while evaluating the module argument `pkgs' in ":anon-11:anon-1":2122 … noting that argument `pkgs` is not externally provided, so querying `_module.args` instead, requiring `config`2324 … while evaluating definitions from `/nix/store/xfg4bws749i95jvnxhymxmfwailzk38q-source/modules/transposition.nix':2526 (stack trace truncated; use '--show-trace' to show the full, detailed trace)2728 error: Nixpkgs 26.11 has dropped support for x86_64-darwin.2930 The 26.05 stable branch still supports x86_64-darwin, and will31 receive security fixes until the end of 2026. If you use channels,32 you can switch to 26.05 as follows:3334 $ sudo nix-channel --add https://nixos.org/channels/nixpkgs-26.05-darwin nixpkgs35 $ sudo nix-channel --update3637 If this doesn’t work, you may need to run:3839 # Lack of sudo is deliberate:40 $ nix-channel --remove nixpkgs4142 If you use flakes, switch your flake input:4344 inputs.nixpkgs = {45 url = "github:NixOS/nixpkgs/nixpkgs-26.05-darwin";46 };4748 See the release notes for more information and alternatives:4950 https://nixos.org/manual/nixpkgs/unstable/release-notes#x86_64-darwin-26.11