cPanel has been arround for years, and a very very popular server management for Web Developers, from novice to expert.
Since the PHP 5.6 will not get any support and update, it is strongly recomended to update to PHP 7.2.
cPanel makes it easy
What you need to do is login, search for an icon named “Select PHP Version”. It will brings you to PHP Selector page. Click on the version dropdown menu, and select the newer version on PHP. Once you click that button, it will follows with PHP version change.
After this action, you can check the website in few cases, some functions and code probably not supported anymore and you need to update them.
More than a year a go, I wrote about how to upgrade PHP 5.6 to PHP 7.0.
Now, PHP 7.0 will reached the end of its critical support through December 2018. After that date PHP community will no longer provides support for bugs. Following to PHP 7.0, PHP 7.1 will be put under discontinued support next year.
In WordPres 4.5, my old function to add a custom size to media uploader seems not working anymore. But I found that new way to add custom size image is a lot simpler using image_size_names_choose filter.
Basically when you create your own image sizes using the add_image_size function:
you can just add the new sizes to image_size_names_choose: