- The packages `signald`, `signaldctl` and `purple-signald` have been dropped as they are unmaintained upstream and have been incompatible with the official Signal servers for a long while.

- Apache Kafka was updated to `>= 4.0.0`. Please note that this is the first release which operates
  entirely without Apache ZooKeeper support, and all clusters need to be migrated to KRaft mode. See
  the [release announcement](https://kafka.apache.org/blog#apache_kafka_400_release_announcement)
  for more details.

- `ast-grep` removes the `sg` command to prevent conflict with the `sg` command from shadow-utils. If you need legacy sg command compatibility with old code, you can use `ast-grep.override { enableLegacySg = true; }`

- rename package `wtf` to `wtfutil`.

- `python3Packages.beancount` was updated to 3.1.0. Previous major version remains available as `python3Packages.beancount_2`.

- `wastebin` has been updated to 3.0.0. See the [Changelog](https://github.com/matze/wastebin/blob/master/CHANGELOG.md#300) for breaking changes to the configuration.

- `binwalk` was updated to 3.1.0, which has been rewritten in Rust. The Python module is no longer available.
  See the release notes of [3.1.0](https://github.com/ReFirmLabs/binwalk/releases/tag/v3.1.0) for more information.

- `pkgs.nextcloud28` and `pkgs.nextcloud29` have been removed since they are out of support upstream.

- `centrifugo` was updated to v6, which uses a new config format. See [upstream documentation](https://centrifugal.dev/docs/getting-started/migration_v6) for migration.

- `teleport` has been upgraded from major version 16 to major version 17.
  Refer to [upstream upgrade instructions](https://goteleport.com/docs/upgrading/overview/)
  and [release notes for v17](https://goteleport.com/docs/changelog/#1701-11152024).

- Emacs lisp build helpers, such as `emacs.pkgs.melpaBuild`, now enables `__structuredAttrs` by default.
  Environment variables have to be passed via the `env` attribute.

- `buildGoModule` now passes environment variables via the `env` attribute. `CGO_ENABLED` should now be specified with `env.CGO_ENABLED` when passing to buildGoModule. Direct specification of `CGO_ENABLED` is now redirected by a compatibility layer with a warning, but will become an error in future releases.

  Go-related environment variables previously shadowed by `buildGoModule` now results in errors when specified directly. Such variables include `GOOS` and `GOARCH`.

  Third-party projects supporting both stable and unstable channels could detect this change through the absence of the `CGO_ENABLED` function argument in `buildGoModule` (`!((lib.functionArgs buildGoModule) ? CGO_ENABLED)`).

- `buildGoPackage` has been removed. Use `buildGoModule` instead. See the [Go section in the nixpkgs manual](https://nixos.org/manual/nixpkgs/unstable/#sec-language-go) for details.

- `buildGoModule` now supports a `goSum` attribute (`null` by default) to optionally provide a path to `go.sum` and correctly enabling rebuilds when the file changes.

- The newly added aliases `go_latest` and `buildGoLatestModule` are now available and can be use to prevent packages like `gopls` from breaking whenever the default toolchain minor version is lagging behind.
  It can also be used _outside of Nixpkgs_ to get fast access to new Go minor versions without having to wait for a staging cycle that will update the default builder/toolchain.

- A [policy documenting the details of Go toolchain and builder upgrades](https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/go/README.md#go-toolchainbuilder-upgrade-policy) in Nixpkgs, as well as rules related to using non-default builders like `buildGo1xxModule` and `buildGoLatestModule` has been added in-tree.

- top-level `playwright` now refers to the github Microsoft/playwright package
  instead of the python tester launcher. You can still refer to the python
  launcher via `python3Packages.toPythonApplication python3Packages.playwright`

- The representation of the flags attributes as shell/environment variables for most Python building setup hooks are now the same as `stdenv.mkDerivation` and other build helpers -- they are space-separated environment variables when `__structuredAttrs = false` and Bash arrays when `__structuredAttrs = true`, and are concatenated to the command without Bash-evaluation. The following behaviour changes are introduced during the conversion: