To upgrade to a newer version of Ubuntu 14.04 LTS (Long-Term Support), you will need to perform a clean install of the new version.
Ubuntu 14.04 LTS reached end of life in April 2019 and is no longer supported. It is not recommended to use an unsupported operating system as it may have security vulnerabilities that are not patched.
To upgrade to a newer version of Ubuntu, follow these steps:
Download the latest version of Ubuntu from the official website (https://ubuntu.com/download).
Create a bootable USB drive or DVD with the Ubuntu installation image.
Back up all important data and files from your current Ubuntu installation.
Boot from the installation media and follow the prompts to install the new version of Ubuntu.
During the installation process, select the option to perform a clean install. This will erase the current installation and install the new version of Ubuntu.
Note: It is recommended to create a backup of your data before performing the upgrade. A clean install will erase all data on the system, so it is important to make sure that you have a copy of your important files.