The latest version of Ubuntu, version 13.04, was released for download today. This version is known as "Raring Ringtail" and marks the halfway point between two Long Term Support releases, which means it will only be supported for 9 months. Version 14.04 is expected to bring Ubuntu to mobile platforms in addition to the desktop, with a different interface being presented on each platform. The latest version features a Developer Preview SDK for those users that are already looking ahead to 14.04 and want to get an early start on their applications. Also available is MIR, a new window system that will eventually replace X Windows. Several updates have been made to the Unity interface, but I really wish they would switch back to GNOME.
Source: Ars Technica