In addition to numerous new and upgraded packages, this release has the following highlights: The default Python 3 interpreter is now CPython 3.7 instead of CPython 3.6.

The following new services were added since the last release: ./programs/nm-applet.nix There is a new security.googleOsLogin module for using OS Login to manage SSH access to Google Compute Engine instances, which supersedes the imperative and broken google-accounts-daemon used in nixos/modules/virtualisation/google-compute-config.nix.

When upgrading from a previous release, please be aware of the following incompatible changes: The minimum version of Nix required to evaluate Nixpkgs is now 2.0. For users of NixOS 18.03 and 19.03, NixOS defaults to Nix 2.0, but supports using Nix 1.11 by setting nix.package = pkgs.nix1;. If this option is set to a Nix 1.11 package, you will need to either unset the option or upgrade it to Nix 2.0. For users of NixOS 17.09, you will first need to upgrade Nix by setting nix.package = pkgs.nixStable2; and run nixos-rebuild switch as the root user. For users of a daemon-less Nix installation on Linux or macOS, you can upgrade Nix by running curl https://nixos.org/nix/install | sh, or prior to doing a channel update, running nix-env -iA nix. If you have already run a channel update and Nix is no longer able to evaluate Nixpkgs, the error message printed should provide adequate directions for upgrading Nix. For users of the Nix daemon on macOS, you can upgrade Nix by running sudo -i sh -c 'nix-channel --update && nix-env -iA nixpkgs.nix'; sudo launchctl stop org.nixos.nix-daemon; sudo launchctl start org.nixos.nix-daemon. The Syncthing state and configuration data has been moved from services.syncthing.dataDir to the newly defined services.syncthing.configDir, which default to /var/lib/syncthing/.config/syncthing. This change makes possible to share synced directories using ACLs without Syncthing resetting the permission on every start. The ntp module now has sane default restrictions. If you're relying on the previous defaults, which permitted all queries and commands from all firewall-permitted sources, you can set services.ntp.restrictDefault and services.ntp.restrictSource to []. Package rabbitmq_server is renamed to rabbitmq-server. The light module no longer uses setuid binaries, but udev rules. As a consequence users of that module have to belong to the video group in order to use the executable (i.e. users.users.yourusername.extraGroups = ["video"];). Buildbot now supports Python 3 and its packages have been moved to pythonPackages. The options services.buildbot-master.package and services.buildbot-worker.package can be used to select the Python 2 or 3 version of the package. Options services.znc.confOptions.networks.name.userName and services.znc.confOptions.networks.name.modulePackages were removed. They were never used for anything and can therefore safely be removed. Package wasm has been renamed proglodyte-wasm. The package wasm will be pointed to ocamlPackages.wasm in 19.09, so make sure to update your configuration if you want to keep proglodyte-wasm When the nixpkgs.pkgs option is set, NixOS will no longer ignore the nixpkgs.overlays option. The old behavior can be recovered by setting nixpkgs.overlays = lib.mkForce [];. OpenSMTPD has been upgraded to version 6.4.0p1. This release makes backwards-incompatible changes to the configuration file format. See man smtpd.conf for more information on the new file format. The versioned postgresql have been renamed to use underscore number seperators. For example, postgresql96 has been renamed to postgresql_9_6. Package consul-ui and passthrough consul.ui have been removed. The package consul now uses upstream releases that vendor the UI into the binary. See #48714 for details. Slurm introduces the new option services.slurm.stateSaveLocation, which is now set to /var/spool/slurm by default (instead of /var/spool). Make sure to move all files to the new directory or to set the option accordingly. The slurmctld now runs as user slurm instead of root. If you want to keep slurmctld running as root, set services.slurm.user = root. The options services.slurm.nodeName and services.slurm.partitionName are now sets of strings to correctly reflect that fact that each of these options can occour more than once in the configuration. The solr package has been upgraded from 4.10.3 to 7.5.0 and has undergone some major changes. The services.solr module has been updated to reflect these changes. Please review http://lucene.apache.org/solr/ carefully before upgrading. Package ckb is renamed to ckb-next, and options hardware.ckb.* are renamed to hardware.ckb-next.*. The option services.xserver.displayManager.job.logToFile which was previously set to true when using the display managers lightdm, sddm or xpra has been reset to the default value (false). Network interface indiscriminate NixOS firewall options (networking.firewall.allow*) are now preserved when also setting interface specific rules such as networking.firewall.interfaces.en0.allow*. These rules continue to use the pseudo device "default" (networking.firewall.interfaces.default.*), and assigning to this pseudo device will override the (networking.firewall.allow*) options. The nscd service now disables all caching of passwd and group databases by default. This was interferring with the correct functioning of the libnss_systemd.so module which is used by systemd to manage uids and usernames in the presence of DynamicUser= in systemd services. This was already the default behaviour in presence of services.sssd.enable = true because nscd caching would interfere with sssd in unpredictable ways as well. Because we're using nscd not for caching, but for convincing glibc to find NSS modules in the nix store instead of an absolute path, we have decided to disable caching globally now, as it's usually not the behaviour the user wants and can lead to surprising behaviour. Furthermore, negative caching of host lookups is also disabled now by default. This should fix the issue of dns lookups failing in the presence of an unreliable network. If the old behaviour is desired, this can be restored by setting the services.nscd.config option with the desired caching parameters. services.nscd.config = '' server-user nscd threads 1 paranoia no debug-level 0 enable-cache passwd yes positive-time-to-live passwd 600 negative-time-to-live passwd 20 suggested-size passwd 211 check-files passwd yes persistent passwd no shared passwd yes enable-cache group yes positive-time-to-live group 3600 negative-time-to-live group 60 suggested-size group 211 check-files group yes persistent group no shared group yes enable-cache hosts yes positive-time-to-live hosts 600 negative-time-to-live hosts 5 suggested-size hosts 211 check-files hosts yes persistent hosts no shared hosts yes ''; See #50316 for details. GitLab Shell previously used the nix store paths for the gitlab-shell command in its authorized_keys file, which might stop working after garbage collection. To circumvent that, we regenerated that file on each startup. As gitlab-shell has now been changed to use /var/run/current-system/sw/bin/gitlab-shell, this is not necessary anymore, but there might be leftover lines with a nix store path. Regenerate the authorized_keys file via sudo -u git -H gitlab-rake gitlab:shell:setup in that case. The pam_unix account module is now loaded with its control field set to required instead of sufficient, so that later PAM account modules that might do more extensive checks are being executed. Previously, the whole account module verification was exited prematurely in case a nss module provided the account name to pam_unix. The LDAP and SSSD NixOS modules already add their NSS modules when enabled. In case your setup breaks due to some later PAM account module previosuly shadowed, or failing NSS lookups, please file a bug. You can get back the old behaviour by manually setting .text]]>. The pam_unix password module is now loaded with its control field set to sufficient instead of required, so that password managed only by later PAM password modules are being executed. Previously, for example, changing an LDAP account's password through PAM was not possible: the whole password module verification was exited prematurely by pam_unix, preventing pam_ldap to manage the password as it should. fish has been upgraded to 3.0. It comes with a number of improvements and backwards incompatible changes. See the fish release notes for more information. The ibus-table input method has had a change in config format, which causes all previous settings to be lost. See this commit message for details. Support for NixOS module system type types.optionSet and lib.mkOption argument options is removed. Use types.submodule instead. (#54637)

The services.matomo module gained the option services.matomo.package which determines the used Matomo version. composableDerivation along with supporting library functions has been removed. The deprecated truecrypt package has been removed and truecrypt attribute is now an alias for veracrypt. VeraCrypt is backward-compatible with TrueCrypt volumes. Note that cryptsetup also supports loading TrueCrypt volumes. The Kubernetes DNS addons, kube-dns, has been replaced with CoreDNS. This change is made in accordance with Kubernetes making CoreDNS the official default starting from Kubernetes v1.11. Please beware that upgrading DNS-addon on existing clusters might induce minor downtime while the DNS-addon terminates and re-initializes. Also note that the DNS-service now runs with 2 pod replicas by default. The desired number of replicas can be configured using: services.kubernetes.addons.dns.replicas. The quassel-webserver package and module was removed from nixpkgs due to the lack of maintainers. The httpd service now saves log files with a .log file extension by default for easier integration with the logrotate service. The owncloud server packages and httpd subservice module were removed from nixpkgs due to the lack of maintainers. It is possible now to uze ZRAM devices as general purpose ephemeral block devices, not only as swap. Using more than 1 device as ZRAM swap is no longer recommended, but is still possible by setting zramSwap.swapDevices explicitly. Default algorithm for ZRAM swap was changed to zstd. Changes to ZRAM algorithm are applied during nixos-rebuild switch, so make sure you have enough swap space on disk to survive ZRAM device rebuild. Alternatively, use nixos-rebuild boot; reboot. Flat volumes are now disabled by default in hardware.pulseaudio. This has been done to prevent applications, which are unaware of this feature, setting their volumes to 100% on startup causing harm to your audio hardware and potentially your ears. With this change application specific volumes are relative to the master volume which can be adjusted independently, whereas before they were absolute; meaning that in effect, it scaled the device-volume with the volume of the loudest application.