In addition to numerous new and upgraded packages, this release has the following highlights: Support is planned until the end of October 2020, handing over to 20.09. Postgresql for NixOS service now defaults to v11. The graphical installer image starts the graphical session automatically. Before you'd be greeted by a tty and asked to enter systemctl start display-manager. It is now possible to disable the display-manager from running by selecting the Disable display-manager quirk in the boot menu. By default zfs pools will now be trimmed on a weekly basis. Trimming is only done on supported devices (i.e. NVME or SSDs) and should improve throughput and lifetime of these devices. It is controlled by the services.zfs.trim.enable varname. The zfs scrub service (services.zfs.autoScrub.enable) and the zfs autosnapshot service (services.zfs.autoSnapshot.enable) are now only enabled if zfs is set in config.boot.initrd.supportedFilesystems or config.boot.supportedFilesystems. These lists will automatically contain zfs as soon as any zfs mountpoint is configured in fileSystems. nixos-option has been rewritten in C++, speeding it up, improving correctness, and adding a --all option which prints all options and their values.

The following new services were added since the last release: The kubernetes kube-proxy now supports a new hostname configuration services.kubernetes.proxy.hostname which has to be set if the hostname of the node should be non default. UPower's configuration is now managed by NixOS and can be customized via services.upower.

When upgrading from a previous release, please be aware of the following incompatible changes: GnuPG is now built without support for a graphical passphrase entry by default. Please enable the gpg-agent user service via the NixOS option programs.gnupg.agent.enable. Note that upstream recommends using gpg-agent and will spawn a gpg-agent on the first invocation of GnuPG anyway. The dynamicHosts option has been removed from the networkd module. Allowing (multiple) regular users to override host entries affecting the whole system opens up a huge attack vector. There seem to be very rare cases where this might be useful. Consider setting system-wide host entries using networking.hosts, provide them via the DNS server in your network, or use environment.etc to add a file into /etc/NetworkManager/dnsmasq.d reconfiguring hostsdir. The 99-main.network file was removed. Maching all network interfaces caused many breakages, see #18962 and #71106. We already don't support the global networking.useDHCP, networking.defaultGateway and networking.defaultGateway6 options if networking.useNetworkd is enabled, but direct users to configure the per-device networking.interfaces.<name>.… options. The stdenv now runs all bash with set -u, to catch the use of undefined variables. Before, it itself used set -u but was careful to unset it so other packages' code ran as before. Now, all bash code is held to the same high standard, and the rather complex stateful manipulation of the options can be discarded. The SLIM Display Manager has been removed, as it has been unmaintained since 2013. Consider migrating to a different display manager such as LightDM (current default in NixOS), SDDM, GDM, or using the startx module which uses Xinitrc. The BEAM package set has been deleted. You will only find there the different interpreters. You should now use the different build tools coming with the languages with sandbox mode disabled. There is now only one Xfce package-set and module. This means attributes, xfce4-14 xfce4-12, and xfceUnstable all now point to the latest Xfce 4.14 packages. And in future NixOS releases will be the latest released version of Xfce available at the time during the releases development (if viable). The phpfpm module now sets PrivateTmp=true in its systemd units for better process isolation. If you rely on /tmp being shared with other services, explicitly override this by setting serviceConfig.PrivateTmp to false for each phpfpm unit. KDE’s old multimedia framework Phonon no longer supports Qt 4. For that reason, Plasma desktop also does not have enableQt4Support option any more. The BeeGFS module has been removed. The osquery module has been removed. Going forward, ~/bin in the users home directory will no longer be in PATH by default. If you depend on this you should set the option environment.homeBinInPath to true. The aforementioned option was added this release. The buildRustCrate infrastructure now produces lib outputs in addition to the out output. This has led to drastically reduced closed sizes for some rust crates since development dependencies are now in the lib output. The packages openobex and obexftp are no longer installed when enabling Bluetooth via hardware.bluetooth.enable. The dump1090 derivation has been changed to use FlightAware's dump1090 as its upstream. However, this version does not have an internal webserver anymore. The assets in the share/dump1090 directory of the derivation can be used in conjunction with an external webserver to replace this functionality. The fourStore and fourStoreEndpoint modules have been removed.

SD images are now compressed by default using bzip2. OpenSSH has been upgraded from 7.9 to 8.1, improving security and adding features but with potential incompatibilities. Consult the release announcement for more information. PRETTY_NAME in /etc/os-release now uses the short rather than full version string.