WARNING: Questions with this tag are now closed as off-topic. Questions about Ubuntu Touch, the mobile version for phones and tablets. It has been given the new name Lomiri by UBports.
Ubuntu Touch is no longer maintained by Canonical and is now a community project.
Ubuntu Touch (previously also known as Ubuntu for Phones, Ubuntu for Devices or Ubuntu Personal) is an unofficial flavor of Ubuntu specially designed for mobile devices like phones and tablets.
A version of Ubunttu for phones was first officially announced at the beginning of 2013 and the first Developer Preview was published on 21 Feb 2013. From 2015 to 2016, multiple consumer devices were available from different hardware vendors.
In April 2017 maintenance of the operating system moved to the UBports Community after Marc Shuttleworth announced the end of Canonical's support for the project. All previously supported devices continue to receive updates.
It is installable on the devices listed here. The operating system can be ported to Android devices using the Halium standardized Libhybris implementation.
Ubuntu Touch uses the Unity 8 desktop environment that runs on the Mir display server. Standard X11 deb-packages can be installed, but the recommended way of distributing software is click packages, because the root-filesystem is read-only by default and over-the-air updates are image-based.
The latest stable release of Ubuntu Touch is based on the Ubuntu 16.04 Xenial Xerus, with a later version in in development based on Ubuntu 20.04 LTS. It is being ported by UBports.
Ubuntu Touch is now called Lomiri.
For further details at wikipedia: http://en.wikipedia.org/wiki/Ubuntu_Touch