- [btrbk](https://digint.ch/btrbk/index.html), a backup tool for btrfs subvolumes, taking advantage of btrfs specific capabilities to create atomic snapshots and transfer them incrementally to your backup locations. Available as [services.btrbk](options.html#opt-services.brtbk.instances).
- [geoipupdate](https://github.com/maxmind/geoipupdate), a GeoIP database updater from MaxMind. Available as [services.geoipupdate](options.html#opt-services.geoipupdate.enable).
- [sourcehut](https://sr.ht), a collection of tools useful for software development. Available as [services.sourcehut](options.html#opt-services.sourcehut.enable).
- [ucarp](https://download.pureftpd.org/pub/ucarp/README), an userspace implementation of the Common Address Redundancy Protocol (CARP). Available as [networking.ucarp](options.html#opt-networking.ucarp.enable).
- Users of flashrom should migrate to [programs.flashrom.enable](options.html#opt-programs.flashrom.enable) and add themselves to the `flashrom` group to be able to access programmers supported by flashrom.
- [buildkite-agent-metrics](https://github.com/buildkite/buildkite-agent-metrics), a command-line tool for collecting Buildkite agent metrics, now has a Prometheus exporter available as [services.prometheus.exporters.buildkite-agent](#opt-services.prometheus.exporters.buildkite-agent.enable).
- [influxdb-exporter](https://github.com/prometheus/influxdb_exporter) a Prometheus exporter that exports metrics received on an InfluxDB compatible endpoint is now available as [services.prometheus.exporters.influxdb](#opt-services.prometheus.exporters.influxdb.enable).
- [mx-puppet-discord](https://github.com/matrix-discord/mx-puppet-discord), a discord puppeting bridge for matrix. Available as [services.mx-puppet-discord](#opt-services.mx-puppet-discord.enable).
- [MeshCentral](https://www.meshcommander.com/meshcentral2/overview), a remote administration service ("TeamViewer but self-hosted and with more features") is now available with a package and a module: [services.meshcentral.enable](#opt-services.meshcentral.enable)
-`consul` was upgraded to a new major release with breaking changes, see [upstream changelog](https://github.com/hashicorp/consul/releases/tag/v1.10.0).
-`yggdrasil` was upgraded to a new major release with breaking changes, see [upstream changelog](https://github.com/yggdrasil-network/yggdrasil-go/releases/tag/v0.4.0).
-`icingaweb2` was upgraded to a new release which requires a manual database upgrade, see [upstream changelog](https://github.com/Icinga/icingaweb2/releases/tag/v2.9.0).
-`tt-rss` was upgraded to the commit on 2021-06-21, which has breaking changes. If you use `services.tt-rss.extraConfig` you should migrate to the `putenv`-style configuration. See [this Discourse post](https://community.tt-rss.org/t/rip-config-php-hello-classes-config-php/4337) in the tt-rss forums for more details.
-`services.uptimed` now uses `/var/lib/uptimed` as its stateDirectory instead of `/var/spool/uptimed`. Make sure to move all files to the new directory.
- Deprecated package aliases in `emacs.pkgs.*` have been removed. These aliases were remnants of the old Emacs package infrastructure. We now use exact upstream names wherever possible.
- The setting [`services.openssh.logLevel`](options.html#opt-services.openssh.logLevel) `"VERBOSE"``"INFO"`. This brings NixOS in line with upstream and other Linux distributions, and reduces log spam on servers due to bruteforcing botnets.
However, if [`services.fail2ban.enable`](options.html#opt-services.fail2ban.enable) is `true`, the `fail2ban` will override the verbosity to `"VERBOSE"`, so that `fail2ban` can observe the failed login attempts from the SSH logs.
- Sway: The terminal emulator `rxvt-unicode` is no longer installed by default via `programs.sway.extraPackages`. The current default configuration uses `alacritty` (and soon `foot`) so this is only an issue when using a customized configuration and not installing `rxvt-unicode` explicitly.
-`python3` now defaults to Python 3.9. Python 3.9 introduces many deprecation warnings, please look at the [What's New In Python 3.9 post](https://docs.python.org/3/whatsnew/3.9.html) for more information.
- The `claws-mail` package now references the new GTK+ 3 release branch, major version 4. To use the GTK+ 2 releases, one can install the `claws-mail-gtk2` package.
- The wordpress module provides a new interface which allows to use different webservers with the new option [`services.wordpress.webserver`](options.html#opt-services.wordpress.webserver). Currently `httpd` and `nginx` are supported. The definitions of wordpress sites should now be set in [`services.wordpress.sites`](options.html#opt-services.wordpress.sites).
Sites definitions that use the old interface are automatically migrated in the new option. This backward compatibility will be removed in 22.05.
- The [networking.wireless.iwd](options.html#opt-networking.wireless.iwd.enable) module has a new [networking.wireless.iwd.settings](options.html#opt-networking.wireless.iwd.settings) option.
- The [services.syncoid.enable](options.html#opt-services.syncoid.enable) module now properly drops ZFS permissions after usage. Before it delegated permissions to whole pools instead of datasets and didn't clean up after execution. You can manually look this up for your pools by running `zfs allow your-pool-name` and use `zfs unallow syncoid your-pool-name` to clean this up.
- Zfs: `latestCompatibleLinuxPackages` is now exported on the zfs package. One can use `boot.kernelPackages = config.boot.zfs.package.latestCompatibleLinuxPackages;` to always track the latest compatible kernel with a given version of zfs.
