Release 14.12 ("Caterpillar", 2014/12/30) {#sec-release-14.12}

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

Systemd has been updated to version 217, which has numerous improvements.
Nix has been updated to 1.8.
NixOS is now based on Glibc 2.20.
KDE has been updated to 4.14.
The default Linux kernel has been updated to 3.14.
If users.mutableUsers is enabled (the default), changes made to the declaration of a user or group will be correctly realised when running nixos-rebuild. For instance, removing a user specification from configuration.nix will cause the actual user account to be deleted. If users.mutableUsers is disabled, it is no longer necessary to specify UIDs or GIDs; if omitted, they are allocated dynamically.

Following new services were added since the last release:

atftpd
bosun
bspwm
chronos
collectd
consul
cpuminer-cryptonight
crashplan
dnscrypt-proxy
docker-registry
docker
etcd
fail2ban
fcgiwrap
fleet
fluxbox
gdm
geoclue2
gitlab
gitolite
gnome3.gnome-documents
gnome3.gnome-online-miners
gnome3.gvfs
gnome3.seahorse
hbase
i2pd
influxdb
kubernetes
liquidsoap
lxc
mailpile
mesos
mlmmj
monetdb
mopidy
neo4j
nsd
openntpd
opentsdb
openvswitch
parallels-guest
peerflix
phd
polipo
prosody
radicale
redmine
riemann
scollector
seeks
siproxd
strongswan
tcsd
teamspeak3
thermald
torque/mrom
torque/server
uhub
unifi
znc
zookeeper

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

The default version of Apache httpd is now 2.4. If you use the extraConfig option to pass literal Apache configuration text, you may need to update it --- see Apache's documentation for details. If you wish to continue to use httpd 2.2, add the following line to your NixOS configuration:
```
{ services.httpd.package = pkgs.apacheHttpd_2_2; }
```
PHP 5.3 has been removed because it is no longer supported by the PHP project. A migration guide is available.
The host side of a container virtual Ethernet pair is now called ve-container-name rather than c-container-name.
GNOME 3.10 support has been dropped. The default GNOME version is now 3.12.
VirtualBox has been upgraded to 4.3.20 release. Users may be required to run rm -rf /tmp/.vbox*. The line imports = [ <nixpkgs/nixos/modules/programs/virtualbox.nix> ] is no longer necessary, use services.virtualboxHost.enable = true instead.

Also, hardening mode is now enabled by default, which means that unless you want to use USB support, you no longer need to be a member of the vboxusers group.
Chromium has been updated to 39.0.2171.65. enablePepperPDF is now enabled by default. chromium*Wrapper packages no longer exist, because upstream removed NSAPI support. chromium-stable has been renamed to chromium.
Python packaging documentation is now part of nixpkgs manual. To override the python packages available to a custom python you now use pkgs.pythonFull.buildEnv.override instead of pkgs.pythonFull.override.
boot.resumeDevice = "8:6" is no longer supported. Most users will want to leave it undefined, which takes the swap partitions automatically. There is an evaluation assertion to ensure that the string starts with a slash.
The system-wide default timezone for NixOS installations changed from CET to UTC. To choose a different timezone for your system, configure time.timeZone in configuration.nix. A fairly complete list of possible values for that setting is available at https://en.wikipedia.org/wiki/List_of_tz_database_time_zones.
GNU screen has been updated to 4.2.1, which breaks the ability to connect to sessions created by older versions of screen.
The Intel GPU driver was updated to the 3.x prerelease version (used by most distributions) and supports DRI3 now.