If you want to upgrade your WordPress installed from Fantastico, just follow the path below:
cPanel --> Fantastico --> Blogs --> WordPress --> Find your Current installation and click 'Upgrade'
Please click here to access our WordPress tutorials and you will find a nice one on how to upgrade your WordPress website.
Please, note that manual upgrades can cause database corruptions, data loss, and break you script/site. This is why it is recommended that you create a backup of your site before proceeding with the upgrade.
If you want to perform an upgrade of a WordPress installed from Softaculous, just follow the steps listed below:
cPanel --> Softaculous --> Blogs --> WordPress. Find your installation and click on the Update icon.
If there is not any Update button/link, this means that the application is up to date and an upgrade is not available at the moment.