-`hardware.nvidia` has a new option `open` that can be used to opt in the opensource version of NVIDIA kernel driver. Note that the driver's support for GeForce and Workstation GPUs is still alpha quality, see [NVIDIA Releases Open-Source GPU Kernel Modules](https://developer.nvidia.com/blog/nvidia-releases-open-source-gpu-kernel-modules/) for the official announcement.
- [syncstorage-rs](https://github.com/mozilla-services/syncstorage-rs), a self-hostable sync server for Firefox. Available as [services.firefox-syncserver](options.html#opt-services.firefox-syncserver.enable).
- [dragonflydb](https://dragonflydb.io/), a modern replacement for Redis and Memcached. Available as [services.dragonflydb](#opt-services.dragonflydb.enable).
- [HBase cluster](https://hbase.apache.org/), a distributed, scalable, big data store. Available as [services.hadoop.hbase](options.html#opt-services.hadoop.hbase.enable).
- [persistent-evdev](https://github.com/aiberia/persistent-evdev), a daemon to add virtual proxy devices that mirror a physical input device but persist even if the underlying hardware is hot-plugged. Available as [services.persistent-evdev](#opt-services.persistent-evdev.enable).
- The `isPowerPC` predicate, found on `platform` attrsets (`hostPlatform`, `buildPlatform`, `targetPlatform`, etc) has been removed in order to reduce confusion. The predicate was was defined such that it matches only the 32-bit big-endian members of the POWER/PowerPC family, despite having a name which would imply a broader set of systems. If you were using this predicate, you can replace `foo.isPowerPC` with `(with foo; isPower && is32bit && isBigEndian)`.
- The `fetchgit` fetcher now uses [cone mode](https://www.git-scm.com/docs/git-sparse-checkout/2.37.0#_internalscone_mode_handling) by default for sparse checkouts. [Non-cone mode](https://www.git-scm.com/docs/git-sparse-checkout/2.37.0#_internalsnon_cone_problems) can be enabled by passing `nonConeMode = true`, but note that non-cone mode is deprecated and this option may be removed alongside a future Git update without notice.
- The Barco ClickShare driver/client package `pkgs.clickshare-csc1` and the option `programs.clickshare-csc1.enable` have been removed,
as it requires `qt4`, which reached its end-of-life 2015 and will no longer be supported by nixpkgs.
[According to Barco](https://www.barco.com/de/support/knowledge-base/4380-can-i-use-linux-os-with-clickshare-base-units) many of their base unit models can be used with Google Chrome and the Google Cast extension.
- xow package removed along with the `hardware.xow` module, due to the project being deprecated in favor of `xone`, which is available via the `hardware.xone` module.
- The `xplr` package has been updated from 0.18.0 to 0.19.0, which brings some breaking changes. See the [upstream release notes](https://github.com/sayanarijit/xplr/releases/tag/v0.19.0) for more details.
-`github-runner` gained support for ephemeral runners and registrations using a personal access token (PAT) instead of a registration token. See `services.github-runner.ephemeral` and `services.github-runner.tokenFile` for details.
- Neo4j was updated from version 3 to version 4. See this [migration guide](https://neo4j.com/docs/upgrade-migration-guide/current/) on how to migrate your Neo4j instance.
- Matrix Synapse now requires entries in the `state_group_edges` table to be unique, in order to prevent accidentally introducing duplicate information (for example, because a database backup was restored multiple times). If your Synapse database already has duplicate rows in this table, this could fail with an error and require manual remediation.
- memtest86+ was updated from 5.00-coreboot-002 to 6.00-beta2. It is now the upstream version from https://www.memtest.org/, as coreboot's fork is no longer available.
- The udisks2 service, available at `services.udisks2.enable`, is now disabled by default. It will automatically be enabled through services and desktop environments as needed.
This also means that polkit will now actually be disabled by default. The default for `security.polkit.enable` was already flipped in the previous release, but udisks2 being enabled by default re-enabled it.
- The `pass-secret-service` package now includes systemd units from upstream, so adding it to the NixOS `services.dbus.packages` option will make it start automatically as a systemd user service when an application tries to talk to the libsecret D-Bus API.
- There is a new module for the `thunar` program (the Xfce file manager), which depends on the `xfconf` dbus service, and also has a dbus service and a systemd unit. The option `services.xserver.desktopManager.xfce.thunarPlugins` has been renamed to `programs.thunar.plugins`, and in a future release it may be removed.