<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-16.09">

<title>Release 16.09 (“Flounder”, 2016/09/30)</title>

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

<itemizedlist>

  <listitem>
    <para>Many NixOS configurations and Nix packages now use
    significantly less disk space, thanks to the <link
    xlink:href="https://github.com/NixOS/nixpkgs/issues/7117">extensive
    work on closure size reduction</link>. For example, the closure
    size of a minimal NixOS container went down from ~424 MiB in 16.03
    to ~212 MiB in 16.09, while the closure size of Firefox went from
    ~651 MiB to ~259 MiB.</para>
  </listitem>

  <listitem>
    <para>To improve security, packages are now <link
    xlink:href="https://github.com/NixOS/nixpkgs/pull/12895">built
    using various hardening features</link>. See the Nixpkgs manual
    for more information.</para>
  </listitem>

  <listitem>
    <para>Support for PXE netboot.  See <xref
    linkend="sec-booting-from-pxe" /> for documentation.</para>
  </listitem>

  <listitem>
    <para>X.org server 1.18. If you use the
    <literal>ati_unfree</literal> driver, 1.17 is still used due to an
    ABI incompatibility.</para>
  </listitem>

  <listitem>
    <para>This release is based on Glibc 2.24, GCC 5.4.0 and systemd
    231. The default Linux kernel remains 4.4.</para>
  </listitem>

</itemizedlist>

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

<itemizedlist>
  <listitem><para><literal>(this will get automatically generated at release time)</literal></para></listitem>
</itemizedlist>

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

<itemizedlist>

  <listitem>
    <para>A large number of packages have been converted to use the multiple outputs feature
      of Nix to greatly reduce the amount of required disk space, as
      mentioned above. This may require changes
      to any custom packages to make them build again; see the relevant chapter in the
      Nixpkgs manual for more information. (Additional caveat to packagers: some packaging conventions
      related to multiple-output packages
      <link xlink:href="https://github.com/NixOS/nixpkgs/pull/14766">were changed</link>
      late (August 2016) in the release cycle and differ from the initial introduction of multiple outputs.)
    </para>
  </listitem>

  <listitem>
    <para>Previous versions of Nixpkgs had support for all versions of the LTS
    Haskell package set. That support has been dropped. The previously provided
    <literal>haskell.packages.lts-x_y</literal> package sets still exist in
    name to aviod breaking user code, but these package sets don't actually
    contain the versions mandated by the corresponding LTS release. Instead,
    our package set it loosely based on the latest available LTS release, i.e.
    LTS 7.x at the time of this writing. New releases of NixOS and Nixpkgs will
    drop those old names entirely. <link
    xlink:href="https://nixos.org/nix-dev/2016-June/020585.html">The
    motivation for this change</link> has been discussed at length on the
    <literal>nix-dev</literal> mailing list and in <link
    xlink:href="https://github.com/NixOS/nixpkgs/issues/14897">Github issue
    #14897</link>. Development strategies for Haskell hackers who want to rely
    on Nix and NixOS have been described in <link
    xlink:href="https://nixos.org/nix-dev/2016-June/020642.html">another
    nix-dev article</link>.</para>
  </listitem>

  <listitem>
    <para>Shell aliases for systemd sub-commands
    <link xlink:href="https://github.com/NixOS/nixpkgs/pull/15598">were dropped</link>:
    <command>start</command>, <command>stop</command>,
    <command>restart</command>, <command>status</command>.</para>
  </listitem>

  <listitem>
    <para>Redis now binds to 127.0.0.1 only instead of listening to all network interfaces. This is the default
    behavior of Redis 3.2</para>
  </listitem>

  <listitem>
    <para>
      <literal>/var/empty</literal> is now immutable. Activation script runs <command>chattr +i</command>
      to forbid any modifications inside the folder. See <link xlink:href="https://github.com/NixOS/nixpkgs/pull/18365">
      the pull request</link> for what bugs this caused.
    </para>
  </listitem>

  <listitem>
    <para>Gitlab's maintainance script
    <command>gitlab-runner</command> was removed and split up into the
    more clearer <command>gitlab-run</command> and
    <command>gitlab-rake</command> scripts, because
    <command>gitlab-runner</command> is a component of Gitlab
    CI.</para>
  </listitem>

  <listitem>
    <para><literal>services.xserver.libinput.accelProfile</literal> default
    changed from <literal>flat</literal> to <literal>adaptive</literal>,
    as per <link xlink:href="https://wayland.freedesktop.org/libinput/doc/latest/group__config.html#gad63796972347f318b180e322e35cee79">
    official documentation</link>.</para>
  </listitem>

  <listitem>
    <para><literal>fonts.fontconfig.ultimate.rendering</literal> was removed
    because our presets were obsolete for some time. New presets are hardcoded
    into FreeType; you can select a preset via <literal>fonts.fontconfig.ultimate.preset</literal>.
    You can customize those presets via ordinary environment variables, using
    <literal>environment.variables</literal>.</para>
  </listitem>

  <listitem>
    <para>The <literal>audit</literal> service is no longer enabled by default.
    Use <literal>security.audit.enable = true</literal> to explicitly enable it.</para>
  </listitem>

  <listitem>
    <para>
      <literal>pkgs.linuxPackages.virtualbox</literal> now contains only the
      kernel modules instead of the VirtualBox user space binaries.
      If you want to reference the user space binaries, you have to use the new
      <literal>pkgs.virtualbox</literal> instead.
    </para>
  </listitem>

  <listitem>
    <para><literal>goPackages</literal> was replaced with separated Go
    applications in appropriate <literal>nixpkgs</literal>
    categories. Each Go package uses its own dependency set. There's
    also a new <literal>go2nix</literal> tool introduced to generate a
    Go package definition from its Go source automatically.</para>
  </listitem>

  <listitem>
    <para><literal>services.mongodb.extraConfig</literal> configuration format
    was changed to YAML.</para>
  </listitem>

  <listitem>
    <para>
      PHP has been upgraded to 7.0
    </para>
  </listitem>
</itemizedlist>


<para>Other notable improvements:</para>

<itemizedlist>

  <listitem><para>Revamped grsecurity/PaX support.  There is now only a single
  general-purpose distribution kernel and the configuration interface has been
  streamlined.  Desktop users should be able to simply set
  <programlisting>security.grsecurity.enable = true</programlisting> to get
  a reasonably secure system without having to sacrifice too much
  functionality.
  </para></listitem>

  <listitem><para>Special filesystems, like <literal>/proc</literal>,
  <literal>/run</literal> and others, now have the same mount options
  as recommended by systemd and are unified across different places in
  NixOS.  Mount options are updated during <command>nixos-rebuild
  switch</command> if possible. One benefit from this is improved
  security — most such filesystems are now mounted with
  <literal>noexec</literal>, <literal>nodev</literal> and/or
  <literal>nosuid</literal> options.</para></listitem>

  <listitem><para>The reverse path filter was interfering with DHCPv4 server
  operation in the past. An exception for DHCPv4 and a new option to log
  packets that were dropped due to the reverse path filter was added
  (<literal>networking.firewall.logReversePathDrops</literal>) for easier
  debugging.</para></listitem>

  <listitem><para>Containers configuration within
  <literal>containers.&lt;name&gt;.config</literal> is <link
  xlink:href="https://github.com/NixOS/nixpkgs/pull/17365">now
  properly typed and checked</link>. In particular, partial
  configurations are merged correctly.</para></listitem>

  <listitem>
    <para>The directory container setuid wrapper programs,
    <filename>/var/setuid-wrappers</filename>, <link
    xlink:href="https://github.com/NixOS/nixpkgs/pull/18124">is now
    updated atomically to prevent failures if the switch to a new
    configuration is interrupted.</link></para>
  </listitem>

  <listitem>
    <para><literal>services.xserver.startGnuPGAgent</literal>
      has been removed due to GnuPG 2.1.x bump. See <link
        xlink:href="https://github.com/NixOS/nixpkgs/commit/5391882ebd781149e213e8817fba6ac3c503740c">
        how to achieve similar behavior</link>. You might need to
      <literal>pkill gpg-agent</literal> after the upgrade
      to prevent a stale agent being in the way.
    </para>
  </listitem>

  <listitem><para>
    <link xlink:href="https://github.com/NixOS/nixpkgs/commit/e561edc322d275c3687fec431935095cfc717147">
    Declarative users could share the uid due to the bug in
    the script handling conflict resolution.
    </link>
  </para></listitem>

  <listitem><para>
    Gummi boot has been replaced using systemd-boot.
  </para></listitem>

  <listitem><para>
    Hydra package and NixOS module were added for convenience.
  </para></listitem>

</itemizedlist>


</section>
