- The `services.mysql.pidDir` option was removed, as it was only used by the wordpress apache-httpd service to wait for mysql to have started up. This can be accomplished by either describing a dependency on mysql.service (preferred) or waiting for the (hardcoded) `/run/mysqld/mysql.sock` file to appear.

- The `services.emby.enable` module has been removed, see `services.jellyfin.enable` instead for a free software fork of Emby. See the Jellyfin documentation: [ Migrating from Emby to Jellyfin ](https://jellyfin.readthedocs.io/en/latest/administrator-docs/migrate-from-emby/)

- IPv6 Privacy Extensions are now enabled by default for undeclared interfaces. The previous behaviour was quite misleading --- even though the default value for `networking.interfaces.*.preferTempAddress` was `true`, undeclared interfaces would not prefer temporary addresses. Now, interfaces not mentioned in the config will prefer temporary addresses. EUI64 addresses can still be set as preferred by explicitly setting the option to `false` for the interface in question.

- Since Bittorrent Sync was superseded by Resilio Sync in 2016, the `bittorrentSync`, `bittorrentSync14`, and `bittorrentSync16` packages have been removed in favor of `resilio-sync`.

  The corresponding module, `services.btsync` has been replaced by the `services.resilio` module.

- The httpd service no longer attempts to start the postgresql service. If you have come to depend on this behaviour then you can preserve the behavior with the following configuration: `systemd.services.httpd.after = [ "postgresql.service" ];`

  The option `services.httpd.extraSubservices` has been marked as deprecated. You may still use this feature, but it will be removed in a future release of NixOS. You are encouraged to convert any httpd subservices you may have written to a full NixOS module.

  Most of the httpd subservices packaged with NixOS have been replaced with full NixOS modules including LimeSurvey, WordPress, and Zabbix. These modules can be enabled using the `services.limesurvey.enable`, `services.mediawiki.enable`, `services.wordpress.enable`, and `services.zabbixWeb.enable` options.

- The option `systemd.network.networks.<name>.routes.*.routeConfig.GatewayOnlink` was renamed to `systemd.network.networks.<name>.routes.*.routeConfig.GatewayOnLink` (capital `L`). This follows [ upstreams renaming ](https://github.com/systemd/systemd/commit/9cb8c5593443d24c19e40bfd4fc06d672f8c554c) of the setting.

- As of this release the NixOps feature `autoLuks` is deprecated. It no longer works with our systemd version without manual intervention.

  Whenever the usage of the module is detected the evaluation will fail with a message explaining why and how to deal with the situation.

  A new knob named `nixops.enableDeprecatedAutoLuks` has been introduced to disable the eval failure and to acknowledge the notice was received and read. If you plan on using the feature please note that it might break with subsequent updates.

  Make sure you set the `_netdev` option for each of the file systems referring to block devices provided by the autoLuks module. Not doing this might render the system in a state where it doesn't boot anymore.

  If you are actively using the `autoLuks` module please let us know in [issue \#62211](https://github.com/NixOS/nixpkgs/issues/62211).

- The setopt declarations will be evaluated at the end of `/etc/zshrc`, so any code in [programs.zsh.interactiveShellInit](options.html#opt-programs.zsh.interactiveShellInit), [programs.zsh.loginShellInit](options.html#opt-programs.zsh.loginShellInit) and [programs.zsh.promptInit](options.html#opt-programs.zsh.promptInit) may break if it relies on those options being set.

- The `prometheus-nginx-exporter` package now uses the official exporter provided by NGINX Inc. Its metrics are differently structured and are incompatible to the old ones. For information about the metrics, have a look at the [official repo](https://github.com/nginxinc/nginx-prometheus-exporter).