Linux kernel 3.13

Ubuntu 14.04 includes the 3.13.0-24.46 Ubuntu Linux kernel which is based on the v3.13.9 upstream stable Linux kernel.

. Networking - Included Open vSwitch 2.0.1 support (including VXLAN), better bonding support, better bridge management and diagnosis and new buffer bloat avoidance measures. We also introduce better TCP connection management in the face of packet loss, plus TCP fastopen and improved attack tolerance

. Scheduling - the default I/O scheduler was changed from CFQ to Deadline.

. Thermal and Power Management - Power management and efficiency continues to be a focus and we saw the inclusion of the Intel RPL (Running AVerage Power Limit) support for enforcing and monitoring power limits on modern Intel processors.

. Virtualization - Various changes as well as major improvements to Xen and KVM.

. Filesystems - general performance and latency improvements have been made across the board for filesystems such as Btrfs, XFS, and Ext4.

. Security - Improvements to AppArmor allow more fine-grained control over applications. The Integrity Measurement Architecture has also been enabled. Packaging updates for signed kernels were also performed as well as EFI boot support.

. Hardware support - ARM multiplatform support has been added, enabling you to build a single ARM kernel image that can boot across multiple hardware platforms. Additionally, the ARM64 and Power architectures are now fully supported.

General updates

Improvements in several applications including Libreoffice: Calc and Writer, AppArmor, Nautilus, Unity, Python, Xorg.

Ubuntu Server

OpenStack Icehouse

Ubuntu 14.04 LTS includes the OpenStack 2014.1 (Icehouse) release of the following projects in Ubuntu main:

OpenStack Compute - Nova OpenStack Identity - Keystone OpenStack Imaging - Glance OpenStack Block Storage - Cinder OpenStack Networking - Neutron OpenStack Object Storage - Swift OpenStack Telemetry - Ceilometer OpenStack Orchestration - Heat OpenStack Dashboard - Horizon

Xen 4.4

Ubuntu 14.04 LTS includes Xen 4.4. This is a significant upgrade from the previous release. Of particular note the xen hypervisor no longer supports 32bit only CPUs on the x86 architecture.

Apache 2.4

Ubuntu 14.04 LTS includes Apache 2.4; this is a major version upgrade from Apache 2.2 in Ubuntu 12.04 LTS

PHP 5.5

PHP has been updated to 5.5, which is a major upgrade from 5.3.

Other upgrades

Ubuntu Touch

For phones and tablets while this Ubuntu Touch release is still not a supported release, it is a relatively "stable" build for wider testing and feedback while Ubuntu Team is still continuing with high velocity towards a going-to-market milestone later.