As part of these changes, the DHCP lease files directory has also been moved from `/var/db/dhcpcd` to `/var/lib/dhcpcd`. This migration is performed automatically, but users may have to update their backup configuration.

- `singularity-tools` have the `storeDir` argument removed from its override interface and use `builtins.storeDir` instead.

- The `mkLayer` and `shellScript` build helpers in `singularity-tools` are deprecated, as they are no longer involved in image-building. Maintainers will remove them in future releases.

- The `rust.toTargetArch`, `rust.toTargetOs`, `rust.toTargetFamily`, `rust.toTargetVendor`, `rust.toRustTarget`, `rust.toRustTargetSpec`, `rust.toRustTargetSpecShort`, and `rust.IsNoStdTarget` functions are deprecated in favour of the `rust.platform.arch`, `rust.platform.os`, `rust.platform.target-family`, `rust.platform.vendor`, `rust.rustcTarget`, `rust.rustcTargetSpec`, `rust.cargoShortTarget`, `rust.cargoEnvVarTarget`, and `rust.isNoStdTarget` platform attributes respectively.

- All Budgie and `budgiePlugins` packages have been moved to top-level (i.e.,
  `budgie.budgie-desktop` is now `budgie-desktop` and `budgiePlugins.budgie-media-player-applet`
  is now `budgie-media-player-applet`).

- The method of safely handling secrets in the `networking.wireless` module has been changed to benefit from a [new feature](https://w1.fi/cgit/hostap/commit/?id=e680a51e94a33591f61edb210926bcb71217a21a) of `wpa_supplicant`.
  The syntax to refer to secrets has changed slightly and the option `networking.wireless.environmentFile` has been replaced by `networking.wireless.secretsFile`; see the description of the latter for how to upgrade.

- NetBox was updated to `>= 4.1.0`.
  Have a look at the breaking changes
  of the [4.0 release](https://github.com/netbox-community/netbox/releases/tag/v4.0.0)
  and the [4.1 release](https://github.com/netbox-community/netbox/releases/tag/v4.1.0),
  make the required changes to your database, if needed,
  then upgrade by setting `services.netbox.package = pkgs.netbox_4_1;`
  in your configuration.

- `services.cgit` now runs as the cgit user by default instead of root.
  This change requires granting access to the repositories to this user or
  setting the appropriate one through `services.cgit.some-instance.user`.

- All Oracle JDKs and JREs (`oraclejdk`, `oraclejdk8`, `oraclejre`, `oraclejre8`,
  `jrePlugin`, `jre8Plugin`, `jdkdistro`, `oraclejdk8distro`, and `oraclejdk11`)
  were dropped due to being unmaintained and heavily insecure. OpenJDK provides
  compatible replacements for JDKs and JREs.

- `gradle_6` was removed due to being [unsupported upstream as of 10 Feb 2023](https://endoflife.date/gradle).
  Additionally, it had numerous security vulnerabilities that were only patched
  in later versions, such as [CVE-2021-29429](https://nvd.nist.gov/vuln/detail/CVE-2021-32751),
  [CVE-2021-29427](https://nvd.nist.gov/vuln/detail/CVE-2021-29427), [CVE-2021-29428](https://nvd.nist.gov/vuln/detail/CVE-2021-29428), and [CVE-2021-32751](https://nvd.nist.gov/vuln/detail/CVE-2021-32751).

- `nvimpager` was updated to version 0.13.0, which changes the order of user and
  nvimpager settings: user commands in `-c` and `--cmd` now override the
  respective default settings because they are executed later.

- `javacard-devkit` was dropped due to having a dependency on the Oracle JDK,
  as well as being several years out-of-date.

- Kubernetes `featureGates` have changed from a `listOf str` to `attrsOf bool`.
  This refactor makes it possible to also disable feature gates, without having
  to use `extraOpts` flags.

  A previous configuration may have looked like this:

  ```nix
  {
    featureGates = [ "EphemeralContainers" ];
    extraOpts = pkgs.lib.concatStringsSep " " (
      [
        ''--feature-gates="CSIMigration=false"''
      ]
    );
  }
  ```

  Using an attribute set instead, the new configuration would be:

  ```nix
  {
    featureGates = {
      EphemeralContainers = true;