In addition to numerous new and upgraded packages, this release has the following highlights: Support is planned until the end of October 2021, handing over to 21.09.

The following new services were added since the last release: Keycloak, an open source identity and access management server with support for OpenID Connect, OAUTH 2.0 and SAML 2.0. See the Keycloak section of the NixOS manual for more information.

When upgrading from a previous release, please be aware of the following incompatible changes: systemd-journal2gelf no longer parses json and expects the receiving system to handle it. How to achieve this with Graylog is described in this GitHub issue. If the services.dbus module is enabled, then the user D-Bus session is now always socket activated. The associated options services.dbus.socketActivated and services.xserver.startDbusSession have therefore been removed and you will receive a warning if they are present in your configuration. This change makes the user D-Bus session available also for non-graphical logins. The option fonts.enableFontDir has been renamed to . The path of font directory has also been changed to /run/current-system/sw/share/X11/fonts, for consistency with other X11 resources. A number of options have been renamed in the kicad interface. oceSupport has been renamed to withOCE, withOCCT has been renamed to withOCC, ngspiceSupport has been renamed to withNgspice, and scriptingSupport has been renamed to withScripting. Additionally, kicad/base.nix no longer provides default argument values since these are provided by kicad/default.nix. The socket for the pdns-recursor module was moved from /var/lib/pdns-recursor to /run/pdns-recursor to match upstream. PowerDNS has been updated from 4.2.x to 4.3.x. Please be sure to review the Upgrade Notes provided by upstream before upgrading. Worth specifically noting is that the service now runs entirely as a dedicated pdns user, instead of starting as root and dropping privileges, as well as the default socket-dir location changing from /var/lib/powerdns to /run/pdns. btc1 has been abandoned upstream, and removed. riak-cs package removed along with services.riak-cs module. stanchion package removed along with services.stanchion module.

The default-version of nextcloud is nextcloud20. Please note that it's not possible to upgrade nextcloud across multiple major versions! This means that it's e.g. not possible to upgrade from nextcloud18 to nextcloud20 in a single deploy. The package can be manually upgraded by setting to nextcloud20. NixOS now emits a deprecation warning if systemd's StartLimitInterval setting is used in a serviceConfig section instead of in a unitConfig; that setting is deprecated and now undocumented for the service section by systemd upstream, but still effective and somewhat buggy there, which can be confusing. See #45785 for details. All services should use or StartLimitIntervalSec in instead.