- `pkgs.mattermostLatest` is now an option to track the latest (non-prerelease) Mattermost release. We test upgrade migrations from ESR releases (`pkgs.mattermost`) to `pkgs.mattermostLatest`.

- A new hardening flag, `nostrictaliasing` was made available, corresponding to the gcc/clang option `-fno-strict-aliasing`.

- The `stackclashprotection` hardening flag has been enabled by default on compilers that support it.

- In `dovecot` package removed hard coding path to module directory.

- `authelia` version 4.39.0 has made some changes which deprecate older configurations.
  They are still expected to be working until future version 5.0.0, but will generate warnings in logs.
  Read the [release notes](https://www.authelia.com/blog/4.39-release-notes/) for human readable summaries of the changes.

- `hddfancontrol` has been updated to major release 2. See the [migration guide](https://github.com/desbma/hddfancontrol/tree/master?tab=readme-ov-file#migrating-from-v1x), as there are breaking changes.

- `nextcloud-news-updater` is unmaintained and was removed from nixpkgs.

- KDE Partition Manager `partitionmanager`'s support for ReiserFS is removed.
  ReiserFS has not been actively maintained for many years. It has been marked as obsolete since Linux 6.6, and
  [is removed](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c01f664e4ca210823b7594b50669bbd9b0a3c3b0)
  in Linux 6.13.

- `gerbera` now has wavpack support.

- `signal-desktop` has been migrated to a from source build. No state migration is necessary. In case there's no working source build available (like on Darwin), the the binary build is still available at `signal-desktop-bin`.

- `ddclient` was updated from 3.11.2 to 4.0.0 [Release notes](https://github.com/ddclient/ddclient/releases/tag/v4.0.0)

## Nixpkgs Library {#sec-nixpkgs-release-25.05-lib}

### Breaking changes {#sec-nixpkgs-release-25.05-lib-breaking}

- Structure of the `functor` of some types has changed. `functor` is an implementation detail and should not be relied upon. If you did rely on it let us know in this [PR](https://github.com/NixOS/nixpkgs/pull/363565).
  - [`lib.types.enum`](https://nixos.org/manual/nixos/unstable/#sec-option-types-basic): Previously the `functor.payload` was the list of enum values directly. Now it is an attribute set containing the values in the `values` attribute.
  - [`lib.types.separatedString`](https://nixos.org/manual/nixos/unstable/#sec-option-types-string): Previously the `functor.payload` was the separator directly. Now it is an attribute set containing the separator in the `sep` attribute.

- [`lib.packagesFromDirectoryRecursive`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.filesystem.packagesFromDirectoryRecursive) now rejects unknown arguments.

### Deprecations {#sec-nixpkgs-release-25.05-lib-deprecations}

- `functor` is an implementation detail and should not be relied upon, but since its status wasn't clear and it has had some use cases without alternatives, changes are being handled as gracefully as possible. Deprecations within functor:
  - `functor.wrapped` is now deprecated for some types and using it will give a warning with migration instructions. It is deprecated for these types:
    - `lib.types.attrsWith`
    - `lib.types.listOf`
    - `lib.types.unique` and `lib.types.uniq`
    - `lib.types.nullOr`
    - `lib.types.functionTo`
    - `lib.types.coercedTo`
    - `lib.types.either`

### Additions and Improvements {#sec-nixpkgs-release-25.05-lib-additions-improvements}

- [`lib.packagesFromDirectoryRecursive`](https://nixos.org/manual/nixpkgs/unstable/#function-library-lib.filesystem.packagesFromDirectoryRecursive) can now construct nested scopes matching the directory tree passed as input.