Does Plesk support PHP 7.1 out of the box?
Why PHP version 7.1 is not shown under "Add and Remove Product Components" for the Plesk 12.5?
PHP 7.1 is not supported by Plesk 12.5. The support is planned to be implemented in future updates.
PHP 7.1 is available for the Plesk Onyx 17.0 and higher.