Updating PHP Version in Plesk
To update your PHP version in Plesk:
1. Log into your Plesk control panel.
2. Go to Websites & Domains
3. Click on PHP Settings.
4. Click on the PHP Support (PHP version) drop down menu and Select your required version from the list
5. Click OK at the bottom of the page to apply the new version.
6. You should now see the new PHP version displayed in your control panel.