The first beta version of the upcoming operating system Ubuntu 16.04 LTS (Xenial Xerus) will be released in a few hours. So developers have stopped adding new features, and are working on optimizing what they added to the new version. 
The upcoming Ubuntu 16.04 LTS distribution will be released with a new kernel (linux-4.4.0-7.22), which is apparently based on the upstream Linux kernel 4.4.2 LTS (Long Term Support) announced by Greg Kroah-Hartman on February 17, 2016.
So the Ubuntu Kernel Team reports in its weekly newsletter that the Ubuntu 16.04 LTS kernel packages will be based on Linux Kernel 4.4.2, urging those who wish to test the upcoming beta and report any problems that they may encounter.
We should mention that in addition to the 4.4.2 kernel, the new Ubuntu 16.04 LTS (Xenial Xerus) has many other important updates, such as the latest version of the LibreOffice 5.1 office suite. Also, GNOME Software is installed by default.
So we expect Ubuntu 1604 LTS will be a great release and will come with the latest software packages, such as the new Mozilla Firefox 45.0 and the Thunderbird 45.0 that will fully support GTK3.
The Xenial Xerus will be officially released at 23 April 2016, but until then, those who are interested can try the Beta version.
