How to Learn PHP Version
You have 3 different options to learn the PHP version of your server:
1. Create a PHP Information File
If you have access to FTP, please extract this file into your root and then visit yoursite.com/phpinfo.php address. You’ll see the version info at the top of the page.
2. Health Check Plugin
Install this plugin: https://wordpress.org/plugins/health-check/ (When you activate it you get a message at the top of the plugins page.)
3. Contact Your Hosting Provider
Ask to your hosting provider or login your hosting control panel (if exists) and you should see it over there. There must be “PHP Settings” or that kind of button/link.