xlink:href="https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html">changes the C++ ABI in an incompatible way</link>; this may cause problems if you try to link objects compiled with different versions of GCC.
xlink:href="https://reproducible-builds.org/">bitwise reproducible builds</link>. For example, <literal>stdenv</literal> now sets the environment variable <envar
xlink:href="https://reproducible-builds.org/specs/source-date-epoch/">SOURCE_DATE_EPOCH</envar> to a deterministic value, and Nix has <link
xlink:href="http://nixos.org/nix/manual/#ssec-relnotes-1.11">gained an option</link> to repeat a build a number of times to test determinism. An ongoing project, the goal of exact reproducibility is to allow binaries to be verified independently (e.g., a user might only trust binaries that appear in three independent binary caches).
Firefox and similar browsers are now <emphasis>wrapped by default</emphasis>. The package and attribute names are plain <literal>firefox</literal> or <literal>midori</literal>, etc. Backward-compatibility attributes were set up, but note that <command>nix-env -u</command> will <emphasis>not</emphasis> update your current <literal>firefox-with-plugins</literal>; you have to uninstall it and install <literal>firefox</literal> instead.
<command>wmiiSnap</command> has been replaced with <command>wmii_hg</command>, but <command>services.xserver.windowManager.wmii.enable</command> has been updated respectively so this only affects you if you have explicitly installed <command>wmiiSnap</command>.
<literal>jobs</literal> NixOS option has been removed. It served as compatibility layer between Upstart jobs and SystemD services. All services have been rewritten to use <literal>systemd.services</literal>
<command>wmiimenu</command> is removed, as it has been removed by the developers upstream. Use <command>wimenu</command> from the <command>wmii-hg</command> package.
Gitit is no longer automatically added to the module list in NixOS and as such there will not be any manual entries for it. You will need to add an import statement to your NixOS configuration in order to use it, e.g.
<command>nginx</command> does not accept flags for enabling and disabling modules anymore. Instead it accepts <literal>modules</literal> argument, which is a list of modules to be built in. All modules now reside in <literal>nginxModules</literal> set. Example configuration:
<command>s3sync</command> is removed, as it hasn't been developed by upstream for 4 years and only runs with ruby 1.8. For an actively-developer alternative look at <command>tarsnap</command> and others.
<literal>tidy-html5</literal> package is removed. Upstream only provided <literal>(lib)tidy5</literal> during development, and now they went back to <literal>(lib)tidy</literal> to work as a drop-in replacement of the original package that has been unmaintained for years. You can (still) use the <literal>html-tidy</literal> package, which got updated to a stable release from this new upstream.
<literal>extraDeviceOptions</literal> argument is removed from <literal>bumblebee</literal> package. Instead there are now two separate arguments: <literal>extraNvidiaDeviceOptions</literal> and <literal>extraNouveauDeviceOptions</literal> for setting extra X11 options for nvidia and nouveau drivers, respectively.
The <literal>Ctrl+Alt+Backspace</literal> key combination no longer kills the X server by default. There's a new option <option>services.xserver.enableCtrlAltBackspace</option> allowing to enable the combination again.
Data directory for Postfix MTA server is moved from <filename>/var/postfix</filename> to <filename>/var/lib/postfix</filename>. Old configurations are migrated automatically. <literal>service.postfix</literal> module has also received many improvements, such as correct directories' access rights, new <literal>aliasFiles</literal> and <literal>mapFiles</literal> options and more.
Filesystem options should now be configured as a list of strings, not a comma-separated string. The old style will continue to work, but print a warning, until the 16.09 release. An example of the new style:
CUPS, installed by <literal>services.printing</literal> module, now has its data directory in <filename>/var/lib/cups</filename>. Old configurations from <filename>/etc/cups</filename> are moved there automatically, but there might be problems. Also configuration options <literal>services.printing.cupsdConf</literal> and <literal>services.printing.cupsdFilesConf</literal> were removed because they had been allowing one to override configuration variables required for CUPS to work at all on NixOS. For most use cases, <literal>services.printing.extraConf</literal> and new option <literal>services.printing.extraFilesConf</literal> should be enough; if you encounter a situation when they are not, please file a bug.
There are also Gutenprint improvements; in particular, a new option <literal>services.printing.gutenprint</literal> is added to enable automatic updating of Gutenprint PPMs; it's greatly recommended to enable it instead of adding <literal>gutenprint</literal> to the <literal>drivers</literal> list.
<literal>services.xserver.vaapiDrivers</literal> has been removed. Use <literal>hardware.opengl.extraPackages{,32}</literal> instead. You can also specify VDPAU drivers there.
<literal>programs.ibus</literal> moved to <literal>i18n.inputMethod.ibus</literal>. The option <literal>programs.ibus.plugins</literal> changed to <literal>i18n.inputMethod.ibus.engines</literal> and the option to enable ibus changed from <literal>programs.ibus.enable</literal> to <literal>i18n.inputMethod.enabled</literal>. <literal>i18n.inputMethod.enabled</literal> should be set to the used input method name, <literal>"ibus"</literal> for ibus. An example of the new style:
<literal>services.udev.extraRules</literal> option now writes rules to <filename>99-local.rules</filename> instead of <filename>10-local.rules</filename>. This makes all the user rules apply after others, so their results wouldn't be overriden by anything else.
Large parts of the <literal>services.gitlab</literal> module has been been rewritten. There are new configuration options available. The <literal>stateDir</literal> option was renamned to <literal>statePath</literal> and the <literal>satellitesDir</literal> option was removed. Please review the currently available options.
The option <option>services.nsd.zones.<name>.data</option> no longer interpret the dollar sign ($) as a shell variable, as such it should not be escaped anymore. Thus the following zone data:
<literal>service.syncthing.dataDir</literal> options now has to point to exact folder where syncthing is writing to. Example configuration should look something like:
<literal>networking.firewall.allowPing</literal> is now enabled by default. Users are encouraged to configure an appropriate rate limit for their machines using the Kernel interface at <filename>/proc/sys/net/ipv4/icmp_ratelimit</filename> and <filename>/proc/sys/net/ipv6/icmp/ratelimit</filename> or using the firewall itself, i.e. by setting the NixOS option <literal>networking.firewall.pingLimit</literal>.
you should either re-run <command>nixos-generate-config</command> or manually replace <literal>"${config.boot.kernelPackages.broadcom_sta}"</literal> by <literal>config.boot.kernelPackages.broadcom_sta</literal> in your <filename>/etc/nixos/hardware-configuration.nix</filename>. More discussion is on <linkxlink:href="https://github.com/NixOS/nixpkgs/pull/12595"> the github issue</link>.
The <literal>services.xserver.startGnuPGAgent</literal> option has been removed. GnuPG 2.1.x changed the way the gpg-agent works, and that new approach no longer requires (or even supports) the "start everything as a child of the agent" scheme we've implemented in NixOS for older versions. To configure the gpg-agent for your X session, add the following code to <filename>~/.bashrc</filename> or some file that’s sourced when your shell is started:
is included in your <filename>~/.gnupg/gpg-agent.conf</filename>. You will need to use <command>ssh-add</command> to re-add your ssh keys. If gpg’s automatic transformation of the private keys to the new format fails, you will need to re-import your private keyring as well:
Input method support was improved. New NixOS modules (fcitx, nabi and uim), fcitx engines (chewing, hangul, m17n, mozc and table-other) and ibus engines (hangul and m17n) have been added.