Ubuntu 16.04 was just released a few hours ago. Here’s the easy way to upgrade to Xenial using the Aptik Migration Utility.
Open a terminal window and run the following commands to install Aptik.
sudo apt-add-repository -y ppa:teejee2008/ppa ; \ sudo apt-get update ; \ sudo apt-get install aptik
Note: Copy-paste the entire text given above. Don’t copy line by line.
Plug-in a portable hard-disk or a USB thumb drive with enough free space (8GB or more is recommended).
Start Aptik from the Application Menu and select a folder on the portable disk as the backup location.