-`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.
- [dragonflydb](https://dragonflydb.io/), a modern replacement for Redis and Memcached. Available as [services.dragonflydb](#opt-services.dragonflydb.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 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.
- A new module was added for the Saleae Logic device family, providing the options `hardware.saleae-logic.enable` and `hardware.saleae-logic.package`.
- 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.