<section xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="sec-release-21.03">
 <title>Release 21.03 (“Okapi”, 2021.03/??)</title>

 <section xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="sec-release-21.03-highlights">
  <title>Highlights</title>

  <para>
   In addition to numerous new and upgraded packages, this release has the
   following highlights:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     Support is planned until the end of October 2021, handing over to 21.09.
    </para>
   </listitem>
   <listitem>
    <para>GNOME desktop environment was upgraded to 3.38, see its <link xlink:href="https://help.gnome.org/misc/release-notes/3.38/">release notes</link>.</para>
   </listitem>
   <listitem>
    <para>
     <link xlink:href="https://www.gnuradio.org/">GNURadio</link> 3.8 was
     <link xlink:href="https://github.com/NixOS/nixpkgs/issues/82263">finnally</link>
     packaged, along with a rewrite to the Nix expressions, allowing users to
     override the features upstream supports selecting to compile or not to.
     Additionally, the attribute <code>gnuradio</code> and <code>gnuradio3_7</code>
     now point to an externally wrapped by default derivations, that allow you to
     also add `extraPythonPackages` to the Python interpreter used by GNURadio.
     Missing environmental variables needed for operational GUI were also added
     (<link xlink:href="https://github.com/NixOS/nixpkgs/issues/75478">#7547</link>).
    </para>
   </listitem>
  </itemizedlist>
 </section>

 <section xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="sec-release-21.03-new-services">
  <title>New Services</title>

  <para>
   The following new services were added since the last release:
  </para>

  <itemizedlist>
   <listitem>
     <para>
       <link xlink:href="https://www.keycloak.org/">Keycloak</link>,
       an open source identity and access management server with
       support for <link
       xlink:href="https://openid.net/connect/">OpenID Connect</link>,
       <link xlink:href="https://oauth.net/2/">OAUTH 2.0</link> and
       <link xlink:href="https://en.wikipedia.org/wiki/SAML_2.0">SAML
       2.0</link>.
     </para>
     <para>
       See the <link linkend="module-services-keycloak">Keycloak
       section of the NixOS manual</link> for more information.
     </para>
   </listitem>
   <listitem>
     <para>
       <xref linkend="opt-services.samba-wsdd.enable" /> Web Services Dynamic Discovery host daemon
     </para>
   </listitem>
  </itemizedlist>

 </section>

 <section xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="sec-release-21.03-incompatibilities">
  <title>Backward Incompatibilities</title>

  <para>
   When upgrading from a previous release, please be aware of the following
   incompatible changes:
  </para>

  <itemizedlist>
    <listitem>
      <para>
        <literal>systemd-journal2gelf</literal> no longer parses json and expects the receiving system to handle it. How to achieve this with Graylog is described in this <link xlink:href="https://github.com/parse-nl/SystemdJournal2Gelf/issues/10">GitHub issue</link>.
      </para>
   </listitem>
   <listitem>
    <para>
     If the <varname>services.dbus</varname> module is enabled, then
     the user D-Bus session is now always socket activated. The
     associated options <varname>services.dbus.socketActivated</varname>
     and <varname>services.xserver.startDbusSession</varname> 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.
    </para>
   </listitem>
   <listitem>
    <para>
     The <varname>networking.wireless.iwd</varname> module now installs
     the upstream-provided 80-iwd.link file, which sets the NamePolicy=
     for all wlan devices to "keep kernel", to avoid race conditions
     between iwd and networkd. If you don't want this, you can set
     <literal>systemd.network.links."80-iwd" = lib.mkForce {}</literal>.
    </para>
   </listitem>
   <listitem>
     <para>
       <literal>rubyMinimal</literal> was removed due to being unused and
       unusable. The default ruby interpreter includes JIT support, which makes
       it reference it's compiler. Since JIT support is probably needed by some
       Gems, it was decided to enable this feature with all cc references by
       default, and allow to build a Ruby derivation without references to cc,
       by setting <literal>jitSupport = false;</literal> in an overlay. See
       <link xlink:href="https://github.com/NixOS/nixpkgs/pull/90151">#90151</link>
       for more info.
     </para>
   </listitem>
   <listitem>
     <para>
       Setting <option>services.openssh.authorizedKeysFiles</option> now also affects which keys <option>security.pam.enableSSHAgentAuth</option> will use.

       WARNING: If you are using these options in combination do make sure that any key paths you use are present in <option>services.openssh.authorizedKeysFiles</option>!
     </para>
   </listitem>
   <listitem>
    <para>
     The option <option>fonts.enableFontDir</option> has been renamed to
     <xref linkend="opt-fonts.fontDir.enable"/>. The path of font directory
     has also been changed to <literal>/run/current-system/sw/share/X11/fonts</literal>,
     for consistency with other X11 resources.
    </para>
   </listitem>
   <listitem>
    <para>
      A number of options have been renamed in the kicad interface. <literal>oceSupport</literal>
      has been renamed to <literal>withOCE</literal>, <literal>withOCCT</literal> has been renamed
      to <literal>withOCC</literal>, <literal>ngspiceSupport</literal> has been renamed to
      <literal>withNgspice</literal>, and <literal>scriptingSupport</literal> has been renamed to
      <literal>withScripting</literal>. Additionally, <literal>kicad/base.nix</literal> no longer
      provides default argument values since these are provided by
      <literal>kicad/default.nix</literal>.
    </para>
   </listitem>
   <listitem>
    <para>
      The socket for the <literal>pdns-recursor</literal> module was moved from <literal>/var/lib/pdns-recursor</literal>
      to <literal>/run/pdns-recursor</literal> to match upstream.
    </para>
   </listitem>
   <listitem>
    <para>
      Paperwork was updated to version 2. The on-disk format slightly changed,
      and it is not possible to downgrade from Paperwork 2 back to Paperwork
      1.3. Back your documents up before upgrading. See <link xlink:href="https://forum.openpaper.work/t/paperwork-2-0/112/5">this thread</link> for more details.
    </para>
   </listitem>
   <listitem>
    <para>
      PowerDNS has been updated from <literal>4.2.x</literal> to <literal>4.3.x</literal>. Please
      be sure to review the <link xlink:href="https://doc.powerdns.com/authoritative/upgrading.html#x-to-4-3-0">Upgrade Notes</link>
      provided by upstream before upgrading. Worth specifically noting is that the service now runs
      entirely as a dedicated <literal>pdns</literal> user, instead of starting as <literal>root</literal>
      and dropping privileges, as well as the default <literal>socket-dir</literal> location changing from
      <literal>/var/lib/powerdns</literal> to <literal>/run/pdns</literal>.
    </para>
   </listitem>
   <listitem>
     <para>
       xfsprogs was update from 4.19 to 5.10. It now enables reflink support by default on filesystem creation.
       Support for reflinks was added with an experimental status to kernel 4.9 and deemed stable in kernel 4.16.
       If you want to be able to mount XFS filesystems created with this release of xfsprogs on kernel releases older than those, you need to format them
       with <literal>mkfs.xfs -m reflink=0</literal>.
     </para>
   </listitem>
   <listitem>
    <para>
      The uWSGI server is now built with POSIX capabilities. As a consequence,
      root is no longer required in emperor mode and the service defaults to
      running as the unprivileged <literal>uwsgi</literal> user. Any additional
      capability can be added via the new option
      <xref linkend="opt-services.uwsgi.capabilities"/>.
      The previous behaviour can be restored by setting:
<programlisting>
  <xref linkend="opt-services.uwsgi.user"/> = "root";
  <xref linkend="opt-services.uwsgi.group"/> = "root";
  <xref linkend="opt-services.uwsgi.instance"/> =
    {
      uid = "uwsgi";
      gid = "uwsgi";
    };
</programlisting>
    </para>
    <para>
      Another incompatibility from the previous release is that vassals running under a
      different user or group need to use <literal>immediate-{uid,gid}</literal>
      instead of the usual <literal>uid,gid</literal> options.
    </para>
   </listitem>
   <listitem>
    <para>
    <package>btc1</package> has been abandoned upstream, and removed.
    </para>
   </listitem>
   <listitem>
    <para>
    <package>cpp_ethereum</package> (aleth) has been abandoned upstream, and removed.
    </para>
   </listitem>
   <listitem>
    <para>
    <package>riak-cs</package> package removed along with <varname>services.riak-cs</varname> module.
    </para>
   </listitem>
   <listitem>
    <para>
    <package>stanchion</package> package removed along with <varname>services.stanchion</varname> module.
    </para>
   </listitem>
   <listitem>
    <para>
     <package>mutt</package> has been updated to a new major version (2.x), which comes with
     some backward incompatible changes that are described in the
     <link xlink:href="http://www.mutt.org/relnotes/2.0/">release notes for Mutt 2.0</link>.
    </para>
   </listitem>
   <listitem>
    <para>
      <literal>vim</literal> switched to Python 3, dropping all Python 2 support.
    </para>
   </listitem>
   <listitem>
     <para>
      <link linkend="opt-boot.zfs.forceImportAll">boot.zfs.forceImportAll</link>
      previously did nothing, but has been fixed. However its default has been
      changed to <literal>false</literal> to preserve the existing default
      behaviour. If you have this explicitly set to <literal>true</literal>,
      please note that your non-root pools will now be forcibly imported.
    </para>
   </listitem>
   <listitem>
    <para>
     <package>openafs</package> now points to <package>openafs_1_8</package>,
     which is the new stable release.  OpenAFS 1.6 was removed.
    </para>
   </listitem>
   <listitem>
    <para>
     MariaDB has been updated to 10.5.
     Before you upgrade, it would be best to take a backup of your database and read
     <link xlink:href="https://mariadb.com/kb/en/upgrading-from-mariadb-104-to-mariadb-105/#incompatible-changes-between-104-and-105">
     Incompatible Changes Between 10.4 and 10.5</link>.
     After the upgrade you will need to run <literal>mysql_upgrade</literal>.
    </para>
   </listitem>
   <listitem>
    <para>
     The TokuDB storage engine dropped in <package>mariadb</package> 10.5 and removed in <package>mariadb</package> 10.6.
     It is recommended to switch to RocksDB. See also <link xlink:href="https://mariadb.com/kb/en/tokudb/">TokuDB</link> and
     <link xlink:href="https://jira.mariadb.org/browse/MDEV-19780">MDEV-19780: Remove the TokuDB storage engine</link>.
    </para>
   </listitem>
   <listitem>
    <para>
      The <literal>openldap</literal> module now has support for OLC-style
      configuration, users of the <literal>configDir</literal> option may wish
      to migrate. If you continue to use <literal>configDir</literal>, ensure that
      <literal>olcPidFile</literal> is set to <literal>/run/slapd/slapd.pid</literal>.
    </para>
    <para>
      As a result, <literal>extraConfig</literal> and <literal>extraDatabaseConfig</literal>
      are removed. To help with migration, you can convert your <literal>slapd.conf</literal>
      file to OLC configuration with the following script (find the location of this
      configuration file by running <literal>systemctl status openldap</literal>, it is the
      <literal>-f</literal> option.
    </para>
    <programlisting>
      TMPDIR=$(mktemp -d)
      slaptest -f /path/to/slapd.conf $TMPDIR
      slapcat -F $TMPDIR -n0 -H 'ldap:///???(!(objectClass=olcSchemaConfig))'
    </programlisting>
    <para>
      This will dump your current configuration in LDIF format, which should be
      straightforward to convert into Nix settings. This does not show your schema
      configuration, as this is unnecessarily verbose for users of the default schemas
      and <literal>slaptest</literal> is buggy with schemas directly in the config file.
    </para>
   </listitem>
   <listitem>
     <para>
       Amazon EC2 and OpenStack Compute (nova) images now re-fetch instance meta data and user data from the instance
       metadata service (IMDS) on each boot. For example: stopping an EC2 instance, changing its user data, and
       restarting the instance will now cause it to fetch and apply the new user data.
     </para>
     <warning>
       <para>
         Specifically, <literal>/etc/ec2-metadata</literal> is re-populated on each boot. Some NixOS scripts that read
         from this directory are guarded to only run if the files they want to manipulate do not already exist, and so
         will not re-apply their changes if the IMDS response changes. Examples: <literal>root</literal>'s SSH key is
         only added if <literal>/root/.ssh/authorized_keys</literal> does not exist, and SSH host keys are only set from
         user data if they do not exist in <literal>/etc/ssh</literal>.
       </para>
     </warning>
   </listitem>
   <listitem>
    <para>
      The <literal>rspamd</literal> services is now sandboxed. It is run as
      a dynamic user instead of root, so secrets and other files may have to
      be moved or their permissions may have to be fixed. The sockets are now
      located in <literal>/run/rspamd</literal> instead of <literal>/run</literal>.
    </para>
   </listitem>
   <listitem>
    <para>
      Enabling the Tor client no longer silently also enables and
      configures Privoxy, and the
      <varname>services.tor.client.privoxy.enable</varname> option has
      been removed.  To enable Privoxy, and to configure it to use
      Tor's faster port, use the following configuration:
    </para>
    <programlisting>
      <xref linkend="opt-services.privoxy.enable" /> = true;
      <xref linkend="opt-services.privoxy.enableTor" /> = true;
    </programlisting>
   </listitem>
   <listitem>
    <para>
      The <literal>services.tor</literal> module has a new exhaustively typed <xref linkend="opt-services.tor.settings" /> option following RFC 0042; backward compatibility with old options has been preserved when aliasing was possible.
      The corresponding systemd service has been hardened,
      but there is a chance that the service still requires more permissions,
      so please report any related trouble on the bugtracker.
      Onion services v3 are now supported in <xref linkend="opt-services.tor.relay.onionServices" />.
      A new <xref linkend="opt-services.tor.openFirewall" /> option as been introduced for allowing connections on all the TCP ports configured.
    </para>
   </listitem>
   <listitem>
     <para>
       The options <literal>services.slurm.dbdserver.storagePass</literal>
       and <literal>services.slurm.dbdserver.configFile</literal> have been removed.
       Use <literal>services.slurm.dbdserver.storagePassFile</literal> instead to provide the database password.
       Extra config options can be given via the option <literal>services.slurm.dbdserver.extraConfig</literal>. The actual configuration file is created on the fly on startup of the service.
       This avoids that the password gets exposed in the nix store.
     </para>
   </listitem>
   <listitem>
     <para>
       The <literal>wafHook</literal> hook does not wrap Python anymore.
       Packages depending on <literal>wafHook</literal> need to include any Python into their <literal>nativeBuildInputs</literal>.
     </para>
   </listitem>
   <listitem>
     <para>
       Starting with version 1.7.0, the project formerly named <literal>CodiMD</literal>
       is now named <literal>HedgeDoc</literal>.
       New installations will no longer use the old name for users, state directories and such, this needs to be considered when moving state to a more recent NixOS installation.
       Based on <xref linkend="opt-system.stateVersion" />, existing installations will continue to work.
     </para>
   </listitem>
   <listitem>
    <para>
     The <package>fish-foreign-env</package> package has been replaced with
     <package>fishPlugins.foreign-env</package>, in which the fish
     functions have been relocated to the
     <literal>vendor_functions.d</literal> directory to be loaded automatically.
    </para>
   </listitem>
   <listitem>
     <para>
       The prometheus json exporter is now managed by the prometheus community. Together with additional features
       some backwards incompatibilities were introduced.
       Most importantly the exporter no longer accepts a fixed command-line parameter to specify the URL of the
       endpoint serving JSON. It now expects this URL to be passed as an URL parameter, when scraping the exporter's
       <literal>/probe</literal> endpoint.
       In the prometheus scrape configuration the scrape target might look like this:
       <programlisting>
http://some.json-exporter.host:7979/probe?target=https://example.com/some/json/endpoint
       </programlisting>
     </para>
     <para>
       Existing configuration for the exporter needs to be updated, but can partially be re-used.
       Documentation is available in the upstream repository and a small example for NixOS is available
       in the corresponding NixOS test.
     </para>
     <para>
       These changes also affect <xref linkend="opt-services.prometheus.exporters.rspamd.enable" />, which is
       just a preconfigured instance of the json exporter.
     </para>
     <para>
       For more information, take a look at the <link xlink:href="https://github.com/prometheus-community/json_exporter">
       official documentation</link> of the json_exporter.
     </para>
   </listitem>
   <listitem>
     <para>
       Androidenv was updated, removing the <literal>includeDocs</literal> and <literal>lldbVersions</literal>
       arguments. Docs only covered a single version of the Android SDK, LLDB is now bundled with the NDK,
       and both are no longer available to download from the Android package repositories. Additionally, since
       the package lists have been updated, some older versions of Android packages may not be bundled. If you
       depend on older versions of Android packages, we recommend overriding the repo.
     </para>
     <para>
       Android packages are now loaded from a repo.json file created by parsing Android repo XML files. The arguments
       <literal>repoJson</literal> and <literal>repoXmls</literal> have been added to allow overriding the built-in
       androidenv repo.json with your own. Additionally, license files are now written to allow compatibility
       with Gradle-based tools, and the <literal>extraLicenses</literal> argument has been added to accept more
       SDK licenses if your project requires it. See the androidenv documentation for more details.
     </para>
   </listitem>
   <listitem>
     <para>
       The attribute <varname>mpi</varname> is now consistently used to
       provide a default, system-wide MPI implementation.
       The default implementation is openmpi, which has been used before by
       all derivations affects by this change.
       Note that all packages that have used <varname>mpi ? null</varname> in the input
       for optional MPI builds, have been changed to the boolean input paramater
       <varname>useMpi</varname> to enable building with MPI.

       Building all packages with <varname>mpich</varname> instead
       of the default <varname>openmpi</varname> can now be achived like this:
       <programlisting>
self: super:
{
 mpi = super.mpich;
}
       </programlisting>
     </para>
   </listitem>
   <listitem>
     <para>
      The Searx module has been updated with the ability to configure the
      service declaratively and uWSGI integration.
      The option <literal>services.searx.configFile</literal> has been renamed
      to <xref linkend="opt-services.searx.settingsFile"/> for consistency with
      the new <xref linkend="opt-services.searx.settings"/>. In addition, the
      <literal>searx</literal> uid and gid reservations have been removed
      since they were not necessary: the service is now running with a
      dynamically allocated uid.
    </para>
   </listitem>
   <listitem>
     <para>
      The libinput module has been updated with the ability to configure mouse and touchpad settings separately.
      The options in <literal>services.xserver.libinput</literal> have been renamed to <literal>services.xserver.libinput.touchpad</literal>,
      while there is a new <literal>services.xserver.libinput.mouse</literal> for mouse related configuration.
     </para>
     <para>
      Since touchpad options no longer apply to all devices, you may want to replicate your touchpad configuration in
      mouse section.
     </para>
   </listitem>
   <listitem>
    <para>
     ALSA OSS emulation (<varname>sound.enableOSSEmulation</varname>) is now disabled by default.
    </para>
   </listitem>
  </itemizedlist>
 </section>

 <section xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="sec-release-21.03-notable-changes">
  <title>Other Notable Changes</title>

  <itemizedlist>
   <listitem>
    <para>
     The Mailman NixOS module (<literal>services.mailman</literal>) has a new
     option <xref linkend="opt-services.mailman.enablePostfix" />, defaulting
     to true, that controls integration with Postfix.
    </para>
    <para>
     If this option is disabled, default MTA config becomes not set and you
     should set the options in <literal>services.mailman.settings.mta</literal>
     according to the desired configuration as described in
     <link xlink:href="https://mailman.readthedocs.io/en/latest/src/mailman/docs/mta.html">Mailman documentation</link>.
    </para>
   </listitem>
   <listitem>
    <para>
     The default-version of <literal>nextcloud</literal> is <package>nextcloud20</package>.
     Please note that it's <emphasis>not</emphasis> possible to upgrade <literal>nextcloud</literal>
     across multiple major versions! This means that it's e.g. not possible to upgrade
     from <package>nextcloud18</package> to <package>nextcloud20</package> in a single deploy.
    </para>
    <para>
     The package can be manually upgraded by setting <xref linkend="opt-services.nextcloud.package" />
     to <package>nextcloud20</package>.
    </para>
   </listitem>
   <listitem>
    <para>
     The setting <xref linkend="opt-services.redis.bind" /> defaults to <literal>127.0.0.1</literal> now, making Redis listen on the loopback interface only, and not all public network interfaces.
    </para>
   </listitem>
   <listitem>
    <para>
     NixOS now emits a deprecation warning if systemd's <literal>StartLimitInterval</literal> setting is used in a <literal>serviceConfig</literal> section instead of in a <literal>unitConfig</literal>; 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 <link xlink:href="https://github.com/NixOS/nixpkgs/issues/45785">#45785</link> for details.
    </para>
    <para>
     All services should use <xref linkend="opt-systemd.services._name_.startLimitIntervalSec" /> or <literal>StartLimitIntervalSec</literal> in <xref linkend="opt-systemd.services._name_.unitConfig" /> instead.
    </para>
   </listitem>
   <listitem>
    <para>
     The Unbound DNS resolver service (<literal>services.unbound</literal>) has been refactored to allow reloading, control sockets and to fix startup ordering issues.
    </para>

    <para>
     It is now possible to enable a local UNIX control socket for unbound by setting the <xref linkend="opt-services.unbound.localControlSocketPath" />
     option.
    </para>

    <para>
     Previously we just applied a very minimal set of restrictions and
     trusted unbound to properly drop root privs and capabilities.
    </para>

    <para>
     As of this we are (for the most part) just using the upstream
     example unit file for unbound. The main difference is that we start
     unbound as <literal>unbound</literal> user with the required capabilities instead of
     letting unbound do the chroot &amp; uid/gid changes.
    </para>

    <para>
     The upstream unit configuration this is based on is a lot stricter with
     all kinds of permissions then our previous variant. It also came with
     the default of having the <literal>Type</literal> set to <literal>notify</literal>, therefore we are now also
     using the <literal>unbound-with-systemd</literal> package here. Unbound will start up,
     read the configuration files and start listening on the configured ports
     before systemd will declare the unit <literal>active (running)</literal>.
     This will likely help with startup order and the occasional race condition during system
     activation where the DNS service is started but not yet ready to answer
     queries. Services depending on <literal>nss-lookup.target</literal> or <literal>unbound.service</literal>
     are now be able to use unbound when those targets have been reached.
    </para>

    <para>
     Aditionally to the much stricter runtime environmet the
     <literal>/dev/urandom</literal> mount lines we previously had in the code (that would
     randomly failed during the stop-phase) have been removed as systemd will take care of those for us.
    </para>

    <para>
     The <literal>preStart</literal> script is now only required if we enabled the trust
      anchor updates (which are still enabled by default).
    </para>

    <para>
     Another benefit of the refactoring is that we can now issue reloads via
     either <literal>pkill -HUP unbound</literal> and <literal>systemctl reload unbound</literal> to reload the
     running configuration without taking the daemon offline. A prerequisite
     of this was that unbound configuration is available on a well known path
     on the file system. We are using the path <literal>/etc/unbound/unbound.conf</literal> as that is the
     default in the CLI tooling which in turn enables us to use
     <literal>unbound-control</literal> without passing a custom configuration location.
    </para>
   </listitem>
   <listitem>
    <para>
     The <literal>services.dnscrypt-proxy2</literal> module now takes the upstream's example configuration and updates it with the user's settings.

     An option has been added to restore the old behaviour if you prefer to declare the configuration from scratch.
    </para>
   </listitem>
   <listitem>
    <para>
     NixOS now defaults to the unified cgroup hierarchy (cgroupsv2).
     See the <link xlink:href="https://www.redhat.com/sysadmin/fedora-31-control-group-v2">Fedora Article for 31</link>
     for details on why this is desirable, and how it impacts containers.
    </para>
    <para>
     If you want to run containers with a runtime that does not yet support cgroupsv2,
     you can switch back to the old behaviour by setting
     <xref linkend="opt-systemd.enableUnifiedCgroupHierarchy"/> = <literal>false</literal>;
     and rebooting.
    </para>
   </listitem>
   <listitem>
    <para>
     PulseAudio was upgraded to 14.0, with changes to the handling of default sinks.
     See its <link xlink:href="https://www.freedesktop.org/wiki/Software/PulseAudio/Notes/14.0/">release notes</link>.
    </para>

    <para>
     GNOME users may wish to delete their <literal>~/.config/pulse</literal> due to the changes to stream routing
     logic. See <link xlink:href="https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/832">PulseAudio bug 832</link>
     for more information.
    </para>
   </listitem>
   <listitem>
    <para>
     The <package>zookeeper</package> package does not provide
     <literal>zooInspector.sh</literal> anymore, as that "contrib" has
     been dropped from upstream releases.
    </para>
   </listitem>
   <listitem>
    <para>
     In the ACME module, the data used to build the hash for the account
     directory has changed to accomodate new features to reduce account
     rate limit issues. This will trigger new account creation on the first
     rebuild following this update. No issues are expected to arise from this,
     thanks to the new account creation handling.
    </para>
   </listitem>
   <listitem>
    <para>
     <xref linkend="opt-users.users._name_.createHome" /> now always ensures home directory permissions to be <literal>0700</literal>.
     Permissions had previously been ignored for already existing home directories, possibly leaving them readable by others.
     The option's description was incorrect regarding ownership management and has been simplified greatly.
    </para>
   </listitem>
   <listitem>
     <para>
       The GNOME desktop manager once again installs <package>gnome3.epiphany</package> by default.
     </para>
   </listitem>
   <listitem>
    <para>
     NixOS now generates empty <literal>/etc/netgroup</literal>.
     <literal>/etc/netgroup</literal> defines network-wide groups and may affect to setups using NIS.
    </para>
   </listitem>
   <listitem>
    <para>
     Platforms, like <varname>stdenv.hostPlatform</varname>, no longer have a <varname>platform</varname> attribute.
     It has been (mostly) flattoned away:
    </para>
    <itemizedlist>
     <listitem><para><varname>platform.gcc</varname> is now <varname>gcc</varname></para></listitem>
     <listitem><para><literal>platform.kernel*</literal> is now <literal>linux-kernel.*</literal></para></listitem>
    </itemizedlist>
    <para>
     Additionally, <varname>platform.kernelArch</varname> moved to the top level as <varname>linuxArch</varname> to match the other <literal>*Arch</literal> variables.
    </para>
    <para>
     The <varname>platform</varname> grouping of these things never meant anything, and was just a historial/implementation artifact that was overdue removal.
    </para>
   </listitem>
  </itemizedlist>
 </section>
</section>
