nix/doc/manual/src/release-notes/rl-next.md

Release X.Y (202?-??-??)

• URL flake references now support percent-encoded characters.

• Path-like flake references now accept arbitrary unicode characters (except # and ?).

• The experimental feature repl-flake is no longer needed, as its functionality is now part of the flakes experimental feature. To get the previous behavior, use the --file/--expr flags accordingly.

• Introduce new flake installable syntax flakeref#.attrPath where the "." prefix denotes no searching of default attribute prefixes like packages.<SYSTEM> or legacyPackages.<SYSTEM>.

• Nix adds apple-virt to the default system features on macOS systems that support virtualization. This is similar to what's done for the kvm system feature on Linux hosts.

• Introduce a new built-in function builtins.convertHash.

• nix-shell shebang lines now support single-quoted arguments.

• builtins.fetchTree is now marked as stable.

• The interface for creating and updating lock files has been overhauled:

  • nix flake lock only creates lock files and adds missing inputs now. It will never update existing inputs.

  • nix flake update does the same, but will update inputs.

    • Passing no arguments will update all inputs of the current flake, just like it already did.
    • Passing input names as arguments will ensure only those are updated. This replaces the functionality of nix flake lock --update-input
    • To operate on a flake outside the current directory, you must now pass --flake path/to/flake.

  • The flake-specific flags --recreate-lock-file and --update-input have been removed from all commands operating on installables. They are superceded by nix flake update.