nixpkgs/nixos/doc/manual/release-notes/rl-1809.xml

<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-18.09">
 <title>Release 18.09 (“Jellyfish”, 2018/10/05)</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-18.09-highlights">
  <title>Highlights</title>

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

  <itemizedlist>
   <listitem>
    <para>
     End of support is planned for end of April 2019, handing over to 19.03.
    </para>
   </listitem>
   <listitem>
    <para>
     Platform support: x86_64-linux and x86_64-darwin as always. Support for
     aarch64-linux is as with the previous releases, not equivalent to the
     x86-64-linux release, but with efforts to reach parity.
    </para>
   </listitem>
   <listitem>
    <para>
     Nix has been updated to 2.1; see its
     <link xlink:href="https://nixos.org/nix/manual/#ssec-relnotes-2.1">release
     notes</link>.
    </para>
   </listitem>
   <listitem>
    <para>
     Core versions: linux: 4.14 LTS (unchanged), glibc: 2.26 → 2.27, gcc: 7
     (unchanged), systemd: 237 → 239.
    </para>
   </listitem>
   <listitem>
    <para>
     Desktop version changes: gnome: 3.26 → 3.28, (KDE) plasma-desktop: 5.12
     → 5.13.
    </para>
   </listitem>
  </itemizedlist>

  <para>
   Notable changes and additions for 18.09 include:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     Support for wrapping binaries using <literal>firejail</literal> has been
     added through <varname>programs.firejail.wrappedBinaries</varname>.
    </para>
    <para>
     For example
    </para>
<programlisting>
programs.firejail = {
  enable = true;
  wrappedBinaries = {
    firefox = "${lib.getBin pkgs.firefox}/bin/firefox";
    mpv = "${lib.getBin pkgs.mpv}/bin/mpv";
  };
};
</programlisting>
    <para>
     This will place <literal>firefox</literal> and <literal>mpv</literal>
     binaries in the global path wrapped by firejail.
    </para>
   </listitem>
   <listitem>
    <para>
     User channels are now in the default <literal>NIX_PATH</literal>, allowing
     users to use their personal <command>nix-channel</command> defined
     channels in <command>nix-build</command> and <command>nix-shell</command>
     commands, as well as in imports like <code>import
     &lt;mychannel&gt;</code>.
    </para>
    <para>
     For example
    </para>
<programlisting>
$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable nixpkgsunstable
$ nix-channel --update
$ nix-build '&lt;nixpkgsunstable&gt;' -A gitFull
$ nix run -f '&lt;nixpkgsunstable&gt;' gitFull
$ nix-instantiate -E '(import &lt;nixpkgsunstable&gt; {}).gitFull'
</programlisting>
   </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-18.09-new-services">
  <title>New Services</title>

  <para>
   A curated selection of new services that were added since the last release:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     The <varname>services.cassandra</varname> module has been reworked and was
     rewritten from scratch. The service has succeeding tests for the versions
     2.1, 2.2, 3.0 and 3.11 of
     <link
     xlink:href="https://cassandra.apache.org/">Apache
     Cassandra</link>.
    </para>
   </listitem>
   <listitem>
    <para>
     There is a new <varname>services.foundationdb</varname> module for
     deploying
     <link xlink:href="https://www.foundationdb.org">FoundationDB</link>
     clusters.
    </para>
   </listitem>
   <listitem>
    <para>
     When enabled the <literal>iproute2</literal> will copy the files expected
     by ip route (e.g., <filename>rt_tables</filename>) in
     <filename>/etc/iproute2</filename>. This allows to write aliases for
     routing tables for instance.
    </para>
   </listitem>
   <listitem>
    <para>
     <varname>services.strongswan-swanctl</varname> is a modern replacement for
     <varname>services.strongswan</varname>. You can use either one of them to
     setup IPsec VPNs but not both at the same time.
    </para>
    <para>
     <varname>services.strongswan-swanctl</varname> uses the
     <link xlink:href="https://wiki.strongswan.org/projects/strongswan/wiki/swanctl">swanctl</link>
     command which uses the modern
     <link xlink:href="https://github.com/strongswan/strongswan/blob/master/src/libcharon/plugins/vici/README.md">vici</link>
     <emphasis>Versatile IKE Configuration Interface</emphasis>. The deprecated
     <literal>ipsec</literal> command used in
     <varname>services.strongswan</varname> is using the legacy
     <link xlink:href="https://github.com/strongswan/strongswan/blob/master/README_LEGACY.md">stroke
     configuration interface</link>.
    </para>
   </listitem>
   <listitem>
    <para>
     The new <varname>services.elasticsearch-curator</varname> service
     periodically curates or manages, your Elasticsearch indices and snapshots.
    </para>
   </listitem>
  </itemizedlist>

  <para>
   Every new services:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     <literal>./config/xdg/autostart.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./config/xdg/icons.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./config/xdg/menus.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./config/xdg/mime.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./hardware/brightnessctl.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./hardware/onlykey.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./hardware/video/uvcvideo/default.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./misc/documentation.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./programs/firejail.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./programs/iftop.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./programs/sedutil.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./programs/singularity.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./programs/xss-lock.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./programs/zsh/zsh-autosuggestions.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/admin/oxidized.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/backup/duplicati.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/backup/restic.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/backup/restic-rest-server.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/cluster/hadoop/default.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/databases/aerospike.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/databases/monetdb.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/desktops/bamf.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/desktops/flatpak.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/desktops/zeitgeist.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/development/bloop.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/development/jupyter/default.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/hardware/lcd.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/hardware/undervolt.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/misc/clipmenu.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/misc/gitweb.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/misc/serviio.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/misc/safeeyes.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/misc/sysprof.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/misc/weechat.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/monitoring/datadog-agent.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/monitoring/incron.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/dnsdist.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/freeradius.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/hans.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/morty.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/ndppd.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/ocserv.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/owamp.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/quagga.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/shadowsocks.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/stubby.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/networking/zeronet.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/security/certmgr.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/security/cfssl.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/security/oauth2_proxy_nginx.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/web-apps/virtlyst.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/web-apps/youtrack.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/web-servers/hitch/default.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/web-servers/hydron.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/web-servers/meguca.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./services/web-servers/nginx/gitweb.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./virtualisation/kvmgt.nix</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>./virtualisation/qemu-guest-agent.nix</literal>
    </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-18.09-incompatibilities">
  <title>Backward Incompatibilities</title>

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

  <itemizedlist>
   <listitem>
    <para>
     The deprecated <varname>services.cassandra</varname> module has seen a
     complete rewrite. (See above.)
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.strict</literal> is removed. Use
     <literal>builtins.seq</literal> instead.
    </para>
   </listitem>
   <listitem>
    <para>
     The <literal>clementine</literal> package points now to the free
     derivation. <literal>clementineFree</literal> is removed now and
     <literal>clementineUnfree</literal> points to the package which is bundled
     with the unfree <literal>libspotify</literal> package.
    </para>
   </listitem>
   <listitem>
    <para>
     The <literal>netcat</literal> package is now taken directly from OpenBSD's
     <literal>libressl</literal>, instead of relying on Debian's fork. The new
     version should be very close to the old version, but there are some minor
     differences. Importantly, flags like -b, -q, -C, and -Z are no longer
     accepted by the nc command.
    </para>
   </listitem>
   <listitem>
    <para>
     The <varname>services.docker-registry.extraConfig</varname> object doesn't
     contain environment variables anymore. Instead it needs to provide an
     object structure that can be mapped onto the YAML configuration defined in
     <link xlink:href="https://github.com/docker/distribution/blob/v2.6.2/docs/configuration.md">the
     <varname>docker/distribution</varname> docs</link>.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>gnucash</literal> has changed from version 2.4 to 3.x. If you've
     been using <literal>gnucash</literal> (version 2.4) instead of
     <literal>gnucash26</literal> (version 2.6) you must open your Gnucash data
     file(s) with <literal>gnucash26</literal> and then save them to upgrade
     the file format. Then you may use your data file(s) with Gnucash 3.x. See
     the upgrade
     <link xlink:href="https://wiki.gnucash.org/wiki/FAQ#Using_Different_Versions.2C_Up_And_Downgrade">documentation</link>.
     Gnucash 2.4 is still available under the attribute
     <literal>gnucash24</literal>.
    </para>
   </listitem>
   <listitem>
    <para>
     <varname>services.munge</varname> now runs as user (and group)
     <literal>munge</literal> instead of root. Make sure the key file is
     accessible to the daemon.
    </para>
   </listitem>
   <listitem>
    <para>
     <varname>dockerTools.buildImage</varname> now uses <literal>null</literal>
     as default value for <varname>tag</varname>, which indicates that the nix
     output hash will be used as tag.
    </para>
   </listitem>
   <listitem>
    <para>
     The ELK stack: <varname>elasticsearch</varname>,
     <varname>logstash</varname> and <varname>kibana</varname> has been
     upgraded from 2.* to 6.3.*. The 2.* versions have been
     <link xlink:href="https://www.elastic.co/support/eol">unsupported since
     last year</link> so they have been removed. You can still use the 5.*
     versions under the names <varname>elasticsearch5</varname>,
     <varname>logstash5</varname> and <varname>kibana5</varname>.
    </para>
    <para>
     The elastic beats: <varname>filebeat</varname>,
     <varname>heartbeat</varname>, <varname>metricbeat</varname> and
     <varname>packetbeat</varname> have had the same treatment: they now target
     6.3.* as well. The 5.* versions are available under the names:
     <varname>filebeat5</varname>, <varname>heartbeat5</varname>,
     <varname>metricbeat5</varname> and <varname>packetbeat5</varname>
    </para>
    <para>
     The ELK-6.3 stack now comes with
     <link xlink:href="https://www.elastic.co/products/x-pack/open">X-Pack by
     default</link>. Since X-Pack is licensed under the
     <link xlink:href="https://github.com/elastic/elasticsearch/blob/master/licenses/ELASTIC-LICENSE.txt">Elastic
     License</link> the ELK packages now have an unfree license. To use them
     you need to specify <literal>allowUnfree = true;</literal> in your nixpkgs
     configuration.
    </para>
    <para>
     Fortunately there is also a free variant of the ELK stack without X-Pack.
     The packages are available under the names:
     <varname>elasticsearch-oss</varname>, <varname>logstash-oss</varname> and
     <varname>kibana-oss</varname>.
    </para>
   </listitem>
   <listitem>
    <para>
     Options
     <literal>boot.initrd.luks.devices.<replaceable>name</replaceable>.yubikey.ramfsMountPoint</literal>
     <literal>boot.initrd.luks.devices.<replaceable>name</replaceable>.yubikey.storage.mountPoint</literal>
     were removed. <literal>luksroot.nix</literal> module never supported more
     than one YubiKey at a time anyway, hence those options never had any
     effect. You should be able to remove them from your config without any
     issues.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>stdenv.system</literal> and <literal>system</literal> in nixpkgs
     now refer to the host platform instead of the build platform. For native
     builds this is not change, let alone a breaking one. For cross builds, it
     is a breaking change, and <literal>stdenv.buildPlatform.system</literal>
     can be used instead for the old behavior. They should be using that
     anyways for clarity.
    </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-18.09-notable-changes">
  <title>Other Notable Changes</title>

  <itemizedlist>
   <listitem>
    <para>
     <literal>dockerTools.pullImage</literal> relies on image digest instead of
     image tag to download the image. The <literal>sha256</literal> of a pulled
     image has to be updated.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.attrNamesToStr</literal> has been deprecated. Use more
     specific concatenation (<literal>lib.concat(Map)StringsSep</literal>)
     instead.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.addErrorContextToAttrs</literal> has been deprecated. Use
     <literal>builtins.addErrorContext</literal> directly.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.showVal</literal> has been deprecated. Use
     <literal>lib.traceSeqN</literal> instead.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.traceXMLVal</literal> has been deprecated. Use
     <literal>lib.traceValFn builtins.toXml</literal> instead.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.traceXMLValMarked</literal> has been deprecated. Use
     <literal>lib.traceValFn (x: str + builtins.toXML x)</literal> instead.
    </para>
   </listitem>
   <listitem>
    <para>
     The <literal>pkgs</literal> argument to NixOS modules can now be set
     directly using <literal>nixpkgs.pkgs</literal>. Previously, only the
     <literal>system</literal>, <literal>config</literal> and
     <literal>overlays</literal> arguments could be used to influence
     <literal>pkgs</literal>.
    </para>
   </listitem>
   <listitem>
    <para>
     A NixOS system can now be constructed more easily based on a preexisting
     invocation of Nixpkgs. For example:
<programlisting>
inherit (pkgs.nixos {
  boot.loader.grub.enable = false;
  fileSystems."/".device = "/dev/xvda1";
}) toplevel kernel initialRamdisk manual;
      </programlisting>
     This benefits evaluation performance, lets you write Nixpkgs packages that
     depend on NixOS images and is consistent with a deployment architecture
     that would be centered around Nixpkgs overlays.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.traceValIfNot</literal> has been deprecated. Use
     <literal>if/then/else</literal> and <literal>lib.traceValSeq</literal>
     instead.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.traceCallXml</literal> has been deprecated. Please complain
     if you use the function regularly.
    </para>
   </listitem>
   <listitem>
    <para>
     The attribute <literal>lib.nixpkgsVersion</literal> has been deprecated in
     favor of <literal>lib.version</literal>. Please refer to the discussion in
     <link xlink:href="https://github.com/NixOS/nixpkgs/pull/39416#discussion_r183845745">NixOS/nixpkgs#39416</link>
     for further reference.
    </para>
   </listitem>
   <listitem>
    <para>
     <literal>lib.recursiveUpdateUntil</literal> was not acting according to
     its specification. It has been fixed to act according to the docstring,
     and a test has been added.
    </para>
   </listitem>
   <listitem>
    <para>
     The module for <option>security.dhparams</option> has two new options now:
    </para>
    <variablelist>
     <varlistentry>
      <term>
       <option>security.dhparams.stateless</option>
      </term>
      <listitem>
       <para>
        Puts the generated Diffie-Hellman parameters into the Nix store instead
        of managing them in a stateful manner in
        <filename class="directory">/var/lib/dhparams</filename>.
       </para>
      </listitem>
     </varlistentry>
     <varlistentry>
      <term>
       <option>security.dhparams.defaultBitSize</option>
      </term>
      <listitem>
       <para>
        The default bit size to use for the generated Diffie-Hellman
        parameters.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
    <note>
     <para>
      The path to the actual generated parameter files should now be queried
      using
      <literal>config.security.dhparams.params.<replaceable>name</replaceable>.path</literal>
      because it might be either in the Nix store or in a directory configured
      by <option>security.dhparams.path</option>.
     </para>
    </note>
    <note>
     <title>For developers:</title>
     <para>
      Module implementers should not set a specific bit size in order to let
      users configure it by themselves if they want to have a different bit
      size than the default (2048).
     </para>
     <para>
      An example usage of this would be:
<programlisting>
{ config, ... }:

{
  security.dhparams.params.myservice = {};
  environment.etc."myservice.conf".text = ''
    dhparams = ${config.security.dhparams.params.myservice.path}
  '';
}
</programlisting>
     </para>
    </note>
   </listitem>
   <listitem>
    <para>
     <literal>networking.networkmanager.useDnsmasq</literal> has been
     deprecated. Use <literal>networking.networkmanager.dns</literal> instead.
    </para>
   </listitem>
   <listitem>
    <para>
     The Kubernetes package has been bumped to major version 1.11. Please
     consult the
     <link xlink:href="https://github.com/kubernetes/kubernetes/blob/release-1.11/CHANGELOG-1.11.md">release
     notes</link> for details on new features and api changes.
    </para>
   </listitem>
   <listitem>
    <para>
     The option
     <varname>services.kubernetes.apiserver.admissionControl</varname> was
     renamed to
     <varname>services.kubernetes.apiserver.enableAdmissionPlugins</varname>.
    </para>
   </listitem>
   <listitem>
    <para>
     Recommended way to access the Kubernetes Dashboard is via HTTPS (TLS)
     Therefore; public service port for the dashboard has changed to 443
     (container port 8443) and scheme to https.
    </para>
   </listitem>
   <listitem>
    <para>
     The option <varname>services.kubernetes.apiserver.address</varname> was
     renamed to <varname>services.kubernetes.apiserver.bindAddress</varname>.
     Note that the default value has changed from 127.0.0.1 to 0.0.0.0.
    </para>
   </listitem>
   <listitem>
    <para>
     The option <varname>services.kubernetes.apiserver.publicAddress</varname>
     was not used and thus has been removed.
    </para>
   </listitem>
   <listitem>
    <para>
     The option
     <varname>services.kubernetes.addons.dashboard.enableRBAC</varname> was
     renamed to
     <varname>services.kubernetes.addons.dashboard.rbac.enable</varname>.
    </para>
   </listitem>
   <listitem>
    <para>
     The Kubernetes Dashboard now has only minimal RBAC permissions by default.
     If dashboard cluster-admin rights are desired, set
     <varname>services.kubernetes.addons.dashboard.rbac.clusterAdmin</varname>
     to true. On existing clusters, in order for the revocation of privileges
     to take effect, the current ClusterRoleBinding for kubernetes-dashboard
     must be manually removed: <literal>kubectl delete clusterrolebinding
     kubernetes-dashboard</literal>
    </para>
   </listitem>
   <listitem>
    <para>
     The <varname>programs.screen</varname> module provides allows to configure
     <literal>/etc/screenrc</literal>, however the module behaved fairly
     counterintuitive as the config exists, but the package wasn't available.
     Since 18.09 <literal>pkgs.screen</literal> will be added to
     <literal>environment.systemPackages</literal>.
    </para>
   </listitem>
   <listitem>
    <para>
     The module <option>services.networking.hostapd</option> now uses WPA2 by
     default.
    </para>
   </listitem>
   <listitem>
    <para>
     <varname>s6Dns</varname>, <varname>s6Networking</varname>,
     <varname>s6LinuxUtils</varname> and <varname>s6PortableUtils</varname>
     renamed to <varname>s6-dns</varname>, <varname>s6-networking</varname>,
     <varname>s6-linux-utils</varname> and <varname>s6-portable-utils</varname>
     respectively.
    </para>
   </listitem>
   <listitem>
    <para>
     The module option <option>nix.useSandbox</option> is now defaulted to
     <literal>true</literal>.
    </para>
   </listitem>
   <listitem>
    <para>
     The config activation script of <literal>nixos-rebuild</literal> now
     <link xlink:href="https://www.freedesktop.org/software/systemd/man/systemctl.html#Manager%20Lifecycle%20Commands">reloads</link>
     all user units for each authenticated user.
    </para>
   </listitem>
   <listitem>
    <para>
     The default display manager is now LightDM. To use SLiM set
     <literal>services.xserver.displayManager.slim.enable</literal> to
     <literal>true</literal>.
    </para>
   </listitem>
   <listitem>
    <para>
     NixOS option descriptions are now automatically broken up into individual
     paragraphs if the text contains two consecutive newlines, so it's no
     longer necessary to use <code>&lt;/para&gt;&lt;para&gt;</code> to start a
     new paragraph.
    </para>
   </listitem>
   <listitem>
    <para>
     Top-level <literal>buildPlatform</literal>,
     <literal>hostPlatform</literal>, and <literal>targetPlatform</literal> in
     Nixpkgs are deprecated. Please use their equivalents in
     <literal>stdenv</literal> instead:
     <literal>stdenv.buildPlatform</literal>,
     <literal>stdenv.hostPlatform</literal>, and
     <literal>stdenv.targetPlatform</literal>.
    </para>
   </listitem>
  </itemizedlist>
 </section>
</section>