<section xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-release-19.09">
  <title>Release 19.09 (<quote>Loris</quote>, 2019/10/09)</title>
  <section xml:id="sec-release-19.09-highlights">
    <title>Highlights</title>
    <para>
      In addition to numerous new and upgraded packages, this release
      has the following highlights:
    </para>
    <itemizedlist>
      <listitem>
        <para>
          End of support is planned for end of April 2020, handing over
          to 20.03.
        </para>
      </listitem>
      <listitem>
        <para>
          Nix has been updated to 2.3; see its
          <link xlink:href="https://nixos.org/nix/manual/#ssec-relnotes-2.3">release
          notes</link>.
        </para>
      </listitem>
      <listitem>
        <para>
          Core version changes:
        </para>
        <para>
          systemd: 239 -&gt; 243
        </para>
        <para>
          gcc: 7 -&gt; 8
        </para>
        <para>
          glibc: 2.27 (unchanged)
        </para>
        <para>
          linux: 4.19 LTS (unchanged)
        </para>
        <para>
          openssl: 1.0 -&gt; 1.1
        </para>
      </listitem>
      <listitem>
        <para>
          Desktop version changes:
        </para>
        <para>
          plasma5: 5.14 -&gt; 5.16
        </para>
        <para>
          gnome3: 3.30 -&gt; 3.32
        </para>
      </listitem>
      <listitem>
        <para>
          PHP now defaults to PHP 7.3, updated from 7.2.
        </para>
      </listitem>
      <listitem>
        <para>
          PHP 7.1 is no longer supported due to upstream not supporting
          this version for the entire lifecycle of the 19.09 release.
        </para>
      </listitem>
      <listitem>
        <para>
          The binfmt module is now easier to use. Additional systems can
          be added through
          <literal>boot.binfmt.emulatedSystems</literal>. For instance,
          <literal>boot.binfmt.emulatedSystems = [ &quot;wasm32-wasi&quot; &quot;x86_64-windows&quot; &quot;aarch64-linux&quot; ];</literal>
          will set up binfmt interpreters for each of those listed
          systems.
        </para>
      </listitem>
      <listitem>
        <para>
          The installer now uses a less privileged
          <literal>nixos</literal> user whereas before we logged in as
          root. To gain root privileges use <literal>sudo -i</literal>
          without a password.
        </para>
      </listitem>
      <listitem>
        <para>
          We've updated to Xfce 4.14, which brings a new module
          <literal>services.xserver.desktopManager.xfce4-14</literal>.
          If you'd like to upgrade, please switch from the
          <literal>services.xserver.desktopManager.xfce</literal> module
          as it will be deprecated in a future release. They're
          incompatibilities with the current Xfce module; it doesn't
          support <literal>thunarPlugins</literal> and it isn't
          recommended to use
          <literal>services.xserver.desktopManager.xfce</literal> and
          <literal>services.xserver.desktopManager.xfce4-14</literal>
          simultaneously or to downgrade from Xfce 4.14 after upgrading.
        </para>
      </listitem>
      <listitem>
        <para>
          The GNOME 3 desktop manager module sports an interface to
          enable/disable core services, applications, and optional GNOME
          packages like games.
        </para>
        <itemizedlist>
          <listitem>
            <para>
              <literal>services.gnome3.core-os-services.enable</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>services.gnome3.core-shell.enable</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>services.gnome3.core-utilities.enable</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>services.gnome3.games.enable</literal>
            </para>
          </listitem>
        </itemizedlist>
        <para>
          With these options we hope to give users finer grained control
          over their systems. Prior to this change you'd either have to
          manually disable options or use
          <literal>environment.gnome3.excludePackages</literal> which
          only excluded the optional applications.
          <literal>environment.gnome3.excludePackages</literal> is now
          unguarded, it can exclude any package installed with
          <literal>environment.systemPackages</literal> in the GNOME 3
          module.
        </para>
      </listitem>
      <listitem>
        <para>
          Orthogonal to the previous changes to the GNOME 3 desktop
          manager module, we've updated all default services and
          applications to match as close as possible to a default
          reference GNOME 3 experience.
        </para>
        <para>
          <emphasis role="strong">The following changes were enacted in
          <literal>services.gnome3.core-utilities.enable</literal></emphasis>
        </para>
        <itemizedlist>
          <listitem>
            <para>
              <literal>accerciser</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>dconf-editor</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>evolution</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>gnome-documents</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>gnome-nettool</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>gnome-power-manager</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>gnome-todo</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>gnome-tweaks</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>gnome-usage</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>gucharmap</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>nautilus-sendto</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>vinagre</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>cheese</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>geary</literal>
            </para>
          </listitem>
        </itemizedlist>
        <para>
          <emphasis role="strong">The following changes were enacted in
          <literal>services.gnome3.core-shell.enable</literal></emphasis>
        </para>
        <itemizedlist>
          <listitem>
            <para>
              <literal>gnome-color-manager</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>orca</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>services.avahi.enable</literal>
            </para>
          </listitem>
        </itemizedlist>
      </listitem>
    </itemizedlist>
  </section>
  <section xml:id="sec-release-19.09-new-services">
    <title>New Services</title>
    <para>
      The following new services were added since the last release:
    </para>
    <itemizedlist>
      <listitem>
        <para>
          <literal>./programs/dwm-status.nix</literal>
        </para>
      </listitem>
      <listitem>
        <para>
          The new <literal>hardware.printers</literal> module allows to
          declaratively configure CUPS printers via the
          <literal>ensurePrinters</literal> and
          <literal>ensureDefaultPrinter</literal> options.
          <literal>ensurePrinters</literal> will never delete existing
          printers, but will make sure that the given printers are
          configured as declared.
        </para>
      </listitem>
      <listitem>
        <para>
          There is a new
          <link xlink:href="options.html#opt-services.system-config-printer.enable">services.system-config-printer.enable</link>
          and
          <link xlink:href="options.html#opt-programs.system-config-printer.enable">programs.system-config-printer.enable</link>
          module for the program of the same name. If you previously had
          <literal>system-config-printer</literal> enabled through some
          other means you should migrate to using one of these modules.
        </para>
        <itemizedlist>
          <listitem>
            <para>
              <literal>services.xserver.desktopManager.plasma5</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>services.xserver.desktopManager.gnome3</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>services.xserver.desktopManager.pantheon</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>services.xserver.desktopManager.mate</literal>
              Note Mate uses
              <literal>programs.system-config-printer</literal> as it
              doesn't use it as a service, but its graphical interface
              directly.
            </para>
          </listitem>
        </itemizedlist>
      </listitem>
      <listitem>
        <para>
          <link xlink:href="options.html#opt-services.blueman.enable">services.blueman.enable</link>
          has been added. If you previously had blueman installed via
          <literal>environment.systemPackages</literal> please migrate
          to using the NixOS module, as this would result in an
          insufficiently configured blueman.
        </para>
      </listitem>
    </itemizedlist>
  </section>
  <section xml:id="sec-release-19.09-incompatibilities">
    <title>Backward Incompatibilities</title>
    <para>
      When upgrading from a previous release, please be aware of the
      following incompatible changes:
    </para>
    <itemizedlist>
      <listitem>
        <para>
          Buildbot no longer supports Python 2, as support was dropped
          upstream in version 2.0.0. Configurations may need to be
          modified to make them compatible with Python 3.
        </para>
      </listitem>
      <listitem>
        <para>
          PostgreSQL now uses <literal>/run/postgresql</literal> as its
          socket directory instead of <literal>/tmp</literal>. So if you
          run an application like eg. Nextcloud, where you need to use
          the Unix socket path as the database host name, you need to
          change it accordingly.
        </para>
      </listitem>
      <listitem>
        <para>
          PostgreSQL 9.4 is scheduled EOL during the 19.09 life cycle
          and has been removed.
        </para>
      </listitem>
      <listitem>
        <para>
          The options
          <literal>services.prometheus.alertmanager.user</literal> and
          <literal>services.prometheus.alertmanager.group</literal> have
          been removed because the alertmanager service is now using
          systemd's
          <link xlink:href="http://0pointer.net/blog/dynamic-users-with-systemd.html">
          DynamicUser mechanism</link> which obviates these options.
        </para>
      </listitem>
      <listitem>
        <para>
          The NetworkManager systemd unit was renamed back from
          network-manager.service to NetworkManager.service for better
          compatibility with other applications expecting this name. The
          same applies to ModemManager where modem-manager.service is
          now called ModemManager.service again.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>services.nzbget.configFile</literal> and
          <literal>services.nzbget.openFirewall</literal> options were
          removed as they are managed internally by the nzbget. The
          <literal>services.nzbget.dataDir</literal> option hadn't
          actually been used by the module for some time and so was
          removed as cleanup.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>services.mysql.pidDir</literal> option was
          removed, as it was only used by the wordpress apache-httpd
          service to wait for mysql to have started up. This can be
          accomplished by either describing a dependency on
          mysql.service (preferred) or waiting for the (hardcoded)
          <literal>/run/mysqld/mysql.sock</literal> file to appear.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>services.emby.enable</literal> module has been
          removed, see <literal>services.jellyfin.enable</literal>
          instead for a free software fork of Emby. See the Jellyfin
          documentation:
          <link xlink:href="https://jellyfin.readthedocs.io/en/latest/administrator-docs/migrate-from-emby/">
          Migrating from Emby to Jellyfin </link>
        </para>
      </listitem>
      <listitem>
        <para>
          IPv6 Privacy Extensions are now enabled by default for
          undeclared interfaces. The previous behaviour was quite
          misleading — even though the default value for
          <literal>networking.interfaces.*.preferTempAddress</literal>
          was <literal>true</literal>, undeclared interfaces would not
          prefer temporary addresses. Now, interfaces not mentioned in
          the config will prefer temporary addresses. EUI64 addresses
          can still be set as preferred by explicitly setting the option
          to <literal>false</literal> for the interface in question.
        </para>
      </listitem>
      <listitem>
        <para>
          Since Bittorrent Sync was superseded by Resilio Sync in 2016,
          the <literal>bittorrentSync</literal>,
          <literal>bittorrentSync14</literal>, and
          <literal>bittorrentSync16</literal> packages have been removed
          in favor of <literal>resilio-sync</literal>.
        </para>
        <para>
          The corresponding module, <literal>services.btsync</literal>
          has been replaced by the <literal>services.resilio</literal>
          module.
        </para>
      </listitem>
      <listitem>
        <para>
          The httpd service no longer attempts to start the postgresql
          service. If you have come to depend on this behaviour then you
          can preserve the behavior with the following configuration:
          <literal>systemd.services.httpd.after = [ &quot;postgresql.service&quot; ];</literal>
        </para>
        <para>
          The option <literal>services.httpd.extraSubservices</literal>
          has been marked as deprecated. You may still use this feature,
          but it will be removed in a future release of NixOS. You are
          encouraged to convert any httpd subservices you may have
          written to a full NixOS module.
        </para>
        <para>
          Most of the httpd subservices packaged with NixOS have been
          replaced with full NixOS modules including LimeSurvey,
          WordPress, and Zabbix. These modules can be enabled using the
          <literal>services.limesurvey.enable</literal>,
          <literal>services.mediawiki.enable</literal>,
          <literal>services.wordpress.enable</literal>, and
          <literal>services.zabbixWeb.enable</literal> options.
        </para>
      </listitem>
      <listitem>
        <para>
          The option
          <literal>systemd.network.networks.&lt;name&gt;.routes.*.routeConfig.GatewayOnlink</literal>
          was renamed to
          <literal>systemd.network.networks.&lt;name&gt;.routes.*.routeConfig.GatewayOnLink</literal>
          (capital <literal>L</literal>). This follows
          <link xlink:href="https://github.com/systemd/systemd/commit/9cb8c5593443d24c19e40bfd4fc06d672f8c554c">
          upstreams renaming </link> of the setting.
        </para>
      </listitem>
      <listitem>
        <para>
          As of this release the NixOps feature
          <literal>autoLuks</literal> is deprecated. It no longer works
          with our systemd version without manual intervention.
        </para>
        <para>
          Whenever the usage of the module is detected the evaluation
          will fail with a message explaining why and how to deal with
          the situation.
        </para>
        <para>
          A new knob named
          <literal>nixops.enableDeprecatedAutoLuks</literal> has been
          introduced to disable the eval failure and to acknowledge the
          notice was received and read. If you plan on using the feature
          please note that it might break with subsequent updates.
        </para>
        <para>
          Make sure you set the <literal>_netdev</literal> option for
          each of the file systems referring to block devices provided
          by the autoLuks module. Not doing this might render the system
          in a state where it doesn't boot anymore.
        </para>
        <para>
          If you are actively using the <literal>autoLuks</literal>
          module please let us know in
          <link xlink:href="https://github.com/NixOS/nixpkgs/issues/62211">issue
          #62211</link>.
        </para>
      </listitem>
      <listitem>
        <para>
          The setopt declarations will be evaluated at the end of
          <literal>/etc/zshrc</literal>, so any code in
          <link xlink:href="options.html#opt-programs.zsh.interactiveShellInit">programs.zsh.interactiveShellInit</link>,
          <link xlink:href="options.html#opt-programs.zsh.loginShellInit">programs.zsh.loginShellInit</link>
          and
          <link xlink:href="options.html#opt-programs.zsh.promptInit">programs.zsh.promptInit</link>
          may break if it relies on those options being set.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>prometheus-nginx-exporter</literal> package now
          uses the offical exporter provided by NGINX Inc. Its metrics
          are differently structured and are incompatible to the old
          ones. For information about the metrics, have a look at the
          <link xlink:href="https://github.com/nginxinc/nginx-prometheus-exporter">official
          repo</link>.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>shibboleth-sp</literal> package has been updated
          to version 3. It is largely backward compatible, for further
          information refer to the
          <link xlink:href="https://wiki.shibboleth.net/confluence/display/SP3/ReleaseNotes">release
          notes</link> and
          <link xlink:href="https://wiki.shibboleth.net/confluence/display/SP3/UpgradingFromV2">upgrade
          guide</link>.
        </para>
        <para>
          Nodejs 8 is scheduled EOL under the lifetime of 19.09 and has
          been dropped.
        </para>
      </listitem>
      <listitem>
        <para>
          By default, prometheus exporters are now run with
          <literal>DynamicUser</literal> enabled. Exporters that need a
          real user, now run under a seperate user and group which
          follow the pattern
          <literal>&lt;exporter-name&gt;-exporter</literal>, instead of
          the previous default <literal>nobody</literal> and
          <literal>nogroup</literal>. Only some exporters are affected
          by the latter, namely the exporters
          <literal>dovecot</literal>, <literal>node</literal>,
          <literal>postfix</literal> and <literal>varnish</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>ibus-qt</literal> package is not installed by
          default anymore when
          <link xlink:href="options.html#opt-i18n.inputMethod.enabled">i18n.inputMethod.enabled</link>
          is set to <literal>ibus</literal>. If IBus support in Qt 4.x
          applications is required, add the <literal>ibus-qt</literal>
          package to your
          <link xlink:href="options.html#opt-environment.systemPackages">environment.systemPackages</link>
          manually.
        </para>
      </listitem>
      <listitem>
        <para>
          The CUPS Printing service now uses socket-based activation by
          default, only starting when needed. The previous behavior can
          be restored by setting
          <literal>services.cups.startWhenNeeded</literal> to
          <literal>false</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>services.systemhealth</literal> module has been
          removed from nixpkgs due to lack of maintainer.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>services.mantisbt</literal> module has been
          removed from nixpkgs due to lack of maintainer.
        </para>
      </listitem>
      <listitem>
        <para>
          Squid 3 has been removed and the <literal>squid</literal>
          derivation now refers to Squid 4.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>services.pdns-recursor.extraConfig</literal>
          option has been replaced by
          <literal>services.pdns-recursor.settings</literal>. The new
          option allows setting extra configuration while being better
          type-checked and mergeable.
        </para>
      </listitem>
      <listitem>
        <para>
          No service depends on <literal>keys.target</literal> anymore
          which is a systemd target that indicates if all
          <link xlink:href="https://nixos.org/nixops/manual/#idm140737322342384">NixOps
          keys</link> were successfully uploaded. Instead,
          <literal>&lt;key-name&gt;-key.service</literal> should be used
          to define a dependency of a key in a service. The full issue
          behind the <literal>keys.target</literal> dependency is
          described at
          <link xlink:href="https://github.com/NixOS/nixpkgs/issues/67265">NixOS/nixpkgs#67265</link>.
        </para>
        <para>
          The following services are affected by this:
        </para>
        <itemizedlist>
          <listitem>
            <para>
              <link xlink:href="options.html#opt-services.dovecot2.enable"><literal>services.dovecot2</literal></link>
            </para>
          </listitem>
          <listitem>
            <para>
              <link xlink:href="options.html#opt-services.nsd.enable"><literal>services.nsd</literal></link>
            </para>
          </listitem>
          <listitem>
            <para>
              <link xlink:href="options.html#opt-services.softether.enable"><literal>services.softether</literal></link>
            </para>
          </listitem>
          <listitem>
            <para>
              <link xlink:href="options.html#opt-services.strongswan.enable"><literal>services.strongswan</literal></link>
            </para>
          </listitem>
          <listitem>
            <para>
              <link xlink:href="options.html#opt-services.strongswan-swanctl.enable"><literal>services.strongswan-swanctl</literal></link>
            </para>
          </listitem>
          <listitem>
            <para>
              <link xlink:href="options.html#opt-services.httpd.enable"><literal>services.httpd</literal></link>
            </para>
          </listitem>
        </itemizedlist>
      </listitem>
      <listitem>
        <para>
          The <literal>security.acme.directory</literal> option has been
          replaced by a read-only
          <literal>security.acme.certs.&lt;cert&gt;.directory</literal>
          option for each certificate you define. This will be a
          subdirectory of <literal>/var/lib/acme</literal>. You can use
          this read-only option to figure out where the certificates are
          stored for a specific certificate. For example, the
          <literal>services.nginx.virtualhosts.&lt;name&gt;.enableACME</literal>
          option will use this directory option to find the certs for
          the virtual host.
        </para>
        <para>
          <literal>security.acme.preDelay</literal> and
          <literal>security.acme.activationDelay</literal> options have
          been removed. To execute a service before certificates are
          provisioned or renewed add a
          <literal>RequiredBy=acme-${cert}.service</literal> to any
          service.
        </para>
        <para>
          Furthermore, the acme module will not automatically add a
          dependency on <literal>lighttpd.service</literal> anymore. If
          you are using certficates provided by letsencrypt for
          lighttpd, then you should depend on the certificate service
          <literal>acme-${cert}.service&gt;</literal> manually.
        </para>
        <para>
          For nginx, the dependencies are still automatically managed
          when
          <literal>services.nginx.virtualhosts.&lt;name&gt;.enableACME</literal>
          is enabled just like before. What changed is that nginx now
          directly depends on the specific certificates that it needs,
          instead of depending on the catch-all
          <literal>acme-certificates.target</literal>. This target unit
          was also removed from the codebase. This will mean nginx will
          no longer depend on certificates it isn't explicitly managing
          and fixes a bug with certificate renewal ordering racing with
          nginx restarting which could lead to nginx getting in a broken
          state as described at
          <link xlink:href="https://github.com/NixOS/nixpkgs/issues/60180">NixOS/nixpkgs#60180</link>.
        </para>
      </listitem>
      <listitem>
        <para>
          The old deprecated <literal>emacs</literal> package sets have
          been dropped. What used to be called
          <literal>emacsPackagesNg</literal> is now simply called
          <literal>emacsPackages</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          <literal>services.xserver.desktopManager.xterm</literal> is
          now disabled by default if <literal>stateVersion</literal> is
          19.09 or higher. Previously the xterm desktopManager was
          enabled when xserver was enabled, but it isn't useful for all
          people so it didn't make sense to have any desktopManager
          enabled default.
        </para>
      </listitem>
      <listitem>
        <para>
          The WeeChat plugin
          <literal>pkgs.weechatScripts.weechat-xmpp</literal> has been
          removed as it doesn't receive any updates from upstream and
          depends on outdated Python2-based modules.
        </para>
      </listitem>
      <listitem>
        <para>
          Old unsupported versions (<literal>logstash5</literal>,
          <literal>kibana5</literal>, <literal>filebeat5</literal>,
          <literal>heartbeat5</literal>, <literal>metricbeat5</literal>,
          <literal>packetbeat5</literal>) of the ELK-stack and Elastic
          beats have been removed.
        </para>
      </listitem>
      <listitem>
        <para>
          For NixOS 19.03, both Prometheus 1 and 2 were available to
          allow for a seamless transition from version 1 to 2 with
          existing setups. Because Prometheus 1 is no longer developed,
          it was removed. Prometheus 2 is now configured with
          <literal>services.prometheus</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          Citrix Receiver (<literal>citrix_receiver</literal>) has been
          dropped in favor of Citrix Workspace
          (<literal>citrix_workspace</literal>).
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>services.gitlab</literal> module has had its
          literal secret options
          (<literal>services.gitlab.smtp.password</literal>,
          <literal>services.gitlab.databasePassword</literal>,
          <literal>services.gitlab.initialRootPassword</literal>,
          <literal>services.gitlab.secrets.secret</literal>,
          <literal>services.gitlab.secrets.db</literal>,
          <literal>services.gitlab.secrets.otp</literal> and
          <literal>services.gitlab.secrets.jws</literal>) replaced by
          file-based versions
          (<literal>services.gitlab.smtp.passwordFile</literal>,
          <literal>services.gitlab.databasePasswordFile</literal>,
          <literal>services.gitlab.initialRootPasswordFile</literal>,
          <literal>services.gitlab.secrets.secretFile</literal>,
          <literal>services.gitlab.secrets.dbFile</literal>,
          <literal>services.gitlab.secrets.otpFile</literal> and
          <literal>services.gitlab.secrets.jwsFile</literal>). This was
          done so that secrets aren't stored in the world-readable nix
          store, but means that for each option you'll have to create a
          file with the same exact string, add &quot;File&quot; to the
          end of the option name, and change the definition to a string
          pointing to the corresponding file; e.g.
          <literal>services.gitlab.databasePassword = &quot;supersecurepassword&quot;</literal>
          becomes
          <literal>services.gitlab.databasePasswordFile = &quot;/path/to/secret_file&quot;</literal>
          where the file <literal>secret_file</literal> contains the
          string <literal>supersecurepassword</literal>.
        </para>
        <para>
          The state path (<literal>services.gitlab.statePath</literal>)
          now has the following restriction: no parent directory can be
          owned by any other user than <literal>root</literal> or the
          user specified in <literal>services.gitlab.user</literal>;
          i.e. if <literal>services.gitlab.statePath</literal> is set to
          <literal>/var/lib/gitlab/state</literal>,
          <literal>gitlab</literal> and all parent directories must be
          owned by either <literal>root</literal> or the user specified
          in <literal>services.gitlab.user</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>networking.useDHCP</literal> option is
          unsupported in combination with
          <literal>networking.useNetworkd</literal> in anticipation of
          defaulting to it. It has to be set to <literal>false</literal>
          and enabled per interface with
          <literal>networking.interfaces.&lt;name&gt;.useDHCP = true;</literal>
        </para>
      </listitem>
      <listitem>
        <para>
          The Twitter client <literal>corebird</literal> has been
          dropped as
          <link xlink:href="https://www.patreon.com/posts/corebirds-future-18921328">it
          is discontinued and does not work against the new Twitter
          API</link>. Please use the fork <literal>cawbird</literal>
          instead which has been adapted to the API changes and is still
          maintained.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>nodejs-11_x</literal> package has been removed as
          it's EOLed by upstream.
        </para>
      </listitem>
      <listitem>
        <para>
          Because of the systemd upgrade, systemd-timesyncd will no
          longer work if <literal>system.stateVersion</literal> is not
          set correctly. When upgrading from NixOS 19.03, please make
          sure that <literal>system.stateVersion</literal> is set to
          <literal>&quot;19.03&quot;</literal>, or lower if the
          installation dates back to an earlier version of NixOS.
        </para>
      </listitem>
      <listitem>
        <para>
          Due to the short lifetime of non-LTS kernel releases package
          attributes like <literal>linux_5_1</literal>,
          <literal>linux_5_2</literal> and <literal>linux_5_3</literal>
          have been removed to discourage dependence on specific non-LTS
          kernel versions in stable NixOS releases. Going forward,
          versioned attributes like <literal>linux_4_9</literal> will
          exist for LTS versions only. Please use
          <literal>linux_latest</literal> or
          <literal>linux_testing</literal> if you depend on non-LTS
          releases. Keep in mind that <literal>linux_latest</literal>
          and <literal>linux_testing</literal> will change versions
          under the hood during the lifetime of a stable release and
          might include breaking changes.
        </para>
      </listitem>
      <listitem>
        <para>
          Because of the systemd upgrade, some network interfaces might
          change their name. For details see
          <link xlink:href="https://www.freedesktop.org/software/systemd/man/systemd.net-naming-scheme.html#History">
          upstream docs</link> or
          <link xlink:href="https://github.com/NixOS/nixpkgs/issues/71086">
          our ticket</link>.
        </para>
      </listitem>
    </itemizedlist>
  </section>
  <section xml:id="sec-release-19.09-notable-changes">
    <title>Other Notable Changes</title>
    <itemizedlist>
      <listitem>
        <para>
          The <literal>documentation</literal> module gained an option
          named <literal>documentation.nixos.includeAllModules</literal>
          which makes the generated configuration.nix 5 manual page
          include all options from all NixOS modules included in a given
          <literal>configuration.nix</literal> configuration file.
          Currently, it is set to <literal>false</literal> by default as
          enabling it frequently prevents evaluation. But the plan is to
          eventually have it set to <literal>true</literal> by default.
          Please set it to <literal>true</literal> now in your
          <literal>configuration.nix</literal> and fix all the bugs it
          uncovers.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>vlc</literal> package gained support for
          Chromecast streaming, enabled by default. TCP port 8010 must
          be open for it to work, so something like
          <literal>networking.firewall.allowedTCPPorts = [ 8010 ];</literal>
          may be required in your configuration. Also consider enabling
          <link xlink:href="https://nixos.wiki/wiki/Accelerated_Video_Playback">
          Accelerated Video Playback</link> for better transcoding
          performance.
        </para>
      </listitem>
      <listitem>
        <para>
          The following changes apply if the
          <literal>stateVersion</literal> is changed to 19.09 or higher.
          For <literal>stateVersion = &quot;19.03&quot;</literal> or
          lower the old behavior is preserved.
        </para>
        <itemizedlist spacing="compact">
          <listitem>
            <para>
              <literal>solr.package</literal> defaults to
              <literal>pkgs.solr_8</literal>.
            </para>
          </listitem>
        </itemizedlist>
      </listitem>
      <listitem>
        <para>
          The <literal>hunspellDicts.fr-any</literal> dictionary now
          ships with <literal>fr_FR.{aff,dic}</literal> which is linked
          to <literal>fr-toutesvariantes.{aff,dic}</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>mysql</literal> service now runs as
          <literal>mysql</literal> user. Previously, systemd did execute
          it as root, and mysql dropped privileges itself. This includes
          <literal>ExecStartPre=</literal> and
          <literal>ExecStartPost=</literal> phases. To accomplish that,
          runtime and data directory setup was delegated to
          RuntimeDirectory and tmpfiles.
        </para>
      </listitem>
      <listitem>
        <para>
          With the upgrade to systemd version 242 the
          <literal>systemd-timesyncd</literal> service is no longer
          using <literal>DynamicUser=yes</literal>. In order for the
          upgrade to work we rely on an activation script to move the
          state from the old to the new directory. The older directory
          (prior <literal>19.09</literal>) was
          <literal>/var/lib/private/systemd/timesync</literal>.
        </para>
        <para>
          As long as the <literal>system.config.stateVersion</literal>
          is below <literal>19.09</literal> the state folder will
          migrated to its proper location
          (<literal>/var/lib/systemd/timesync</literal>), if required.
        </para>
      </listitem>
      <listitem>
        <para>
          The package <literal>avahi</literal> is now built to look up
          service definitions from
          <literal>/etc/avahi/services</literal> instead of its output
          directory in the nix store. Accordingly the module
          <literal>avahi</literal> now supports custom service
          definitions via
          <literal>services.avahi.extraServiceFiles</literal>, which are
          then placed in the aforementioned directory. See
          avahi.service5 for more information on custom service
          definitions.
        </para>
      </listitem>
      <listitem>
        <para>
          Since version 0.1.19, <literal>cargo-vendor</literal> honors
          package includes that are specified in the
          <literal>Cargo.toml</literal> file of Rust crates.
          <literal>rustPlatform.buildRustPackage</literal> uses
          <literal>cargo-vendor</literal> to collect and build dependent
          crates. Since this change in <literal>cargo-vendor</literal>
          changes the set of vendored files for most Rust packages, the
          hash that use used to verify the dependencies,
          <literal>cargoSha256</literal>, also changes.
        </para>
        <para>
          The <literal>cargoSha256</literal> hashes of all in-tree
          derivations that use <literal>buildRustPackage</literal> have
          been updated to reflect this change. However, third-party
          derivations that use <literal>buildRustPackage</literal> may
          have to be updated as well.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>consul</literal> package was upgraded past
          version <literal>1.5</literal>, so its deprecated legacy UI is
          no longer available.
        </para>
      </listitem>
      <listitem>
        <para>
          The default resample-method for PulseAudio has been changed
          from the upstream default <literal>speex-float-1</literal> to
          <literal>speex-float-5</literal>. Be aware that low-powered
          ARM-based and MIPS-based boards will struggle with this so
          you'll need to set
          <literal>hardware.pulseaudio.daemon.config.resample-method</literal>
          back to <literal>speex-float-1</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>phabricator</literal> package and associated
          <literal>httpd.extraSubservice</literal>, as well as the
          <literal>phd</literal> service have been removed from nixpkgs
          due to lack of maintainer.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>mercurial</literal>
          <literal>httpd.extraSubservice</literal> has been removed from
          nixpkgs due to lack of maintainer.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>trac</literal>
          <literal>httpd.extraSubservice</literal> has been removed from
          nixpkgs because it was unmaintained.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>foswiki</literal> package and associated
          <literal>httpd.extraSubservice</literal> have been removed
          from nixpkgs due to lack of maintainer.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>tomcat-connector</literal>
          <literal>httpd.extraSubservice</literal> has been removed from
          nixpkgs.
        </para>
      </listitem>
      <listitem>
        <para>
          It's now possible to change configuration in
          <link xlink:href="options.html#opt-services.nextcloud.enable">services.nextcloud</link>
          after the initial deploy since all config parameters are
          persisted in an additional config file generated by the
          module. Previously core configuration like database parameters
          were set using their imperative installer after creating
          <literal>/var/lib/nextcloud</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          There exists now <literal>lib.forEach</literal>, which is like
          <literal>map</literal>, but with arguments flipped. When
          mapping function body spans many lines (or has nested
          <literal>map</literal>s), it is often hard to follow which
          list is modified.
        </para>
        <para>
          Previous solution to this problem was either to use
          <literal>lib.flip map</literal> idiom or extract that
          anonymous mapping function to a named one. Both can still be
          used but <literal>lib.forEach</literal> is preferred over
          <literal>lib.flip map</literal>.
        </para>
        <para>
          The <literal>/etc/sysctl.d/nixos.conf</literal> file
          containing all the options set via
          <link xlink:href="options.html#opt-boot.kernel.sysctl">boot.kernel.sysctl</link>
          was moved to <literal>/etc/sysctl.d/60-nixos.conf</literal>,
          as sysctl.d5 recommends prefixing all filenames in
          <literal>/etc/sysctl.d</literal> with a two-digit number and a
          dash to simplify the ordering of the files.
        </para>
      </listitem>
      <listitem>
        <para>
          We now install the sysctl snippets shipped with systemd.
        </para>
        <itemizedlist>
          <listitem>
            <para>
              Loose reverse path filtering
            </para>
          </listitem>
          <listitem>
            <para>
              Source route filtering
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>fq_codel</literal> as a packet scheduler (this
              helps to fight bufferbloat)
            </para>
          </listitem>
        </itemizedlist>
        <para>
          This also configures the kernel to pass core dumps to
          <literal>systemd-coredump</literal>, and restricts the SysRq
          key combinations to the sync command only. These sysctl
          snippets can be found in
          <literal>/etc/sysctl.d/50-*.conf</literal>, and overridden via
          <link xlink:href="options.html#opt-boot.kernel.sysctl">boot.kernel.sysctl</link>
          (which will place the parameters in
          <literal>/etc/sysctl.d/60-nixos.conf</literal>).
        </para>
      </listitem>
      <listitem>
        <para>
          Core dumps are now processed by
          <literal>systemd-coredump</literal> by default.
          <literal>systemd-coredump</literal> behaviour can still be
          modified via <literal>systemd.coredump.extraConfig</literal>.
          To stick to the old behaviour (having the kernel dump to a
          file called <literal>core</literal> in the working directory),
          without piping it through <literal>systemd-coredump</literal>,
          set <literal>systemd.coredump.enable</literal> to
          <literal>false</literal>.
        </para>
      </listitem>
      <listitem>
        <para>
          <literal>systemd.packages</literal> option now also supports
          generators and shutdown scripts. Old
          <literal>systemd.generator-packages</literal> option has been
          removed.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>rmilter</literal> package was removed with
          associated module and options due deprecation by upstream
          developer. Use <literal>rspamd</literal> in proxy mode
          instead.
        </para>
      </listitem>
      <listitem>
        <para>
          systemd cgroup accounting via the
          <link xlink:href="options.html#opt-systemd.enableCgroupAccounting">systemd.enableCgroupAccounting</link>
          option is now enabled by default. It now also enables the more
          recent Block IO and IP accounting features.
        </para>
      </listitem>
      <listitem>
        <para>
          We no longer enable custom font rendering settings with
          <literal>fonts.fontconfig.penultimate.enable</literal> by
          default. The defaults from fontconfig are sufficient.
        </para>
      </listitem>
      <listitem>
        <para>
          The <literal>crashplan</literal> package and the
          <literal>crashplan</literal> service have been removed from
          nixpkgs due to crashplan shutting down the service, while the
          <literal>crashplansb</literal> package and
          <literal>crashplan-small-business</literal> service have been
          removed from nixpkgs due to lack of maintainer.
        </para>
        <para>
          The
          <link xlink:href="options.html#opt-services.redis.enable">redis
          module</link> was hardcoded to use the
          <literal>redis</literal> user, <literal>/run/redis</literal>
          as runtime directory and <literal>/var/lib/redis</literal> as
          state directory. Note that the NixOS module for Redis now
          disables kernel support for Transparent Huge Pages (THP),
          because this features causes major performance problems for
          Redis, e.g. (https://redis.io/topics/latency).
        </para>
      </listitem>
      <listitem>
        <para>
          Using <literal>fonts.enableDefaultFonts</literal> adds a
          default emoji font <literal>noto-fonts-emoji</literal>.
        </para>
        <itemizedlist>
          <listitem>
            <para>
              <literal>services.xserver.enable</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>programs.sway.enable</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>programs.way-cooler.enable</literal>
            </para>
          </listitem>
          <listitem>
            <para>
              <literal>services.xrdp.enable</literal>
            </para>
          </listitem>
        </itemizedlist>
      </listitem>
      <listitem>
        <para>
          The <literal>altcoins</literal> categorization of packages has
          been removed. You now access these packages at the top level,
          ie. <literal>nix-shell -p dogecoin</literal> instead of
          <literal>nix-shell -p altcoins.dogecoin</literal>, etc.
        </para>
      </listitem>
      <listitem>
        <para>
          Ceph has been upgraded to v14.2.1. See the
          <link xlink:href="https://ceph.com/releases/v14-2-0-nautilus-released/">release
          notes</link> for details. The mgr dashboard as well as osds
          backed by loop-devices is no longer explicitly supported by
          the package and module. Note: There's been some issues with
          python-cherrypy, which is used by the dashboard and prometheus
          mgr modules (and possibly others), hence
          0000-dont-check-cherrypy-version.patch.
        </para>
      </listitem>
      <listitem>
        <para>
          <literal>pkgs.weechat</literal> is now compiled against
          <literal>pkgs.python3</literal>. Weechat also recommends
          <link xlink:href="https://weechat.org/scripts/python3/">to use
          Python3 in their docs.</link>
        </para>
      </listitem>
    </itemizedlist>
  </section>
</section>
