Depending on your environment you must manually upgrade the Ubuntu 14.04 to 16.04 version.

Procedure

  1. Show all Linux Standard Base and distribution-specific information.

    lsb_release -a

  2. Install packages using the apt tool.

    sudo apt update

  3. Fetch the latest packages.

    sudo apt-get upgrade

  4. Handle dependencies such as substituting obsolete packages with new packages.

    sudo apt dist-upgrade

  5. Upgrade to the Ubuntu 16.04 version.

    do-release-upgrade

  6. If you have an existing transport node in your Ubuntu KVM host, backup the /etc/network/interfaces file.