- The [services.postgresql.dataDir](options.html#opt-services.postgresql.dataDir) option is now set to `"/var/lib/postgresql/${cfg.package.psqlSchema}"` regardless of your [system.stateVersion](options.html#opt-system.stateVersion). Users with an existing postgresql install that have a [system.stateVersion](options.html#opt-system.stateVersion) of `17.03` or below should double check what the value of their [services.postgresql.dataDir](options.html#opt-services.postgresql.dataDir) option is (`/var/db/postgresql`) and then explicitly set this value to maintain compatibility:
```nix
{
services.postgresql.dataDir = "/var/db/postgresql";
}
```
The postgresql module now expects there to be a database super user account called `postgres` regardless of your [system.stateVersion](options.html#opt-system.stateVersion). Users with an existing postgresql install that have a [system.stateVersion](options.html#opt-system.stateVersion) of `17.03` or below should run the following SQL statements as a database super admin user before upgrading:
```SQL
CREATE ROLE postgres LOGIN SUPERUSER;
```
- The USBGuard module now removes options and instead hardcodes values for `IPCAccessControlFiles`, `ruleFiles`, and `auditFilePath`. Audit logs can be found in the journal.
- The NixOS module system now evaluates option definitions more strictly, allowing it to detect a larger set of problems. As a result, what previously evaluated may not do so anymore. See [the PR that changed this](https://github.com/NixOS/nixpkgs/pull/82743#issuecomment-674520472) for more info.
- For NixOS configuration options, the type `loaOf`, after its initial deprecation in release 20.03, has been removed. In NixOS and Nixpkgs options using this type have been converted to `attrsOf`. For more information on this change have look at these links: [issue \#1800](https://github.com/NixOS/nixpkgs/issues/1800), [PR \#63103](https://github.com/NixOS/nixpkgs/pull/63103).
- `config.systemd.services.${name}.path` now returns a list of paths instead of a colon-separated string.
- Caddy module now uses Caddy v2 by default. Caddy v1 can still be used by setting [services.caddy.package](options.html#opt-services.caddy.package) to `pkgs.caddy1`.
New option [services.caddy.adapter](options.html#opt-services.caddy.adapter) has been added.
- The [jellyfin](options.html#opt-services.jellyfin.enable) module will use and stay on the Jellyfin version `10.5.5` if `stateVersion` is lower than `20.09`. This is because significant changes were made to the database schema, and it is highly recommended to backup your instance before upgrading. After making your backup, you can upgrade to the latest version either by setting your `stateVersion` to `20.09` or higher, or set the `services.jellyfin.package` to `pkgs.jellyfin`. If you do not wish to upgrade Jellyfin, but want to change your `stateVersion`, you can set the value of `services.jellyfin.package` to `pkgs.jellyfin_10_5`.
- The `security.rngd` service is now disabled by default. This choice was made because there's krngd in the linux kernel space making it (for most usecases) functionally redundant.
- The `hardware.nvidia.optimus_prime.enable` service has been renamed to `hardware.nvidia.prime.sync.enable` and has many new enhancements. Related nvidia prime settings may have also changed.
- The package nextcloud17 has been removed and nextcloud18 was marked as insecure since both of them will [ will be EOL (end of life) within the lifetime of 20.09](https://docs.nextcloud.com/server/19/admin_manual/release_schedule.html).
It's necessary to upgrade to nextcloud19:
- From nextcloud17, you have to upgrade to nextcloud18 first as Nextcloud doesn't allow going multiple major revisions forward in a single upgrade. This is possible by setting [services.nextcloud.package](options.html#opt-services.nextcloud.package) to nextcloud18.
- From nextcloud18, it's possible to directly upgrade to nextcloud19 by setting [services.nextcloud.package](options.html#opt-services.nextcloud.package) to nextcloud19.