nginx + php 5.6 in ISP?

Question

PHP

Good afternoon. All the time there was a bunch of nginx + php-fpm, but now I needed a newer version of PHP (5.6-5.7).
Any way to install?
I installed alternative PHP versions, but I can't select them in the site config.

I also tried to remove php-fpm, but I still could not choose.
I don’t want to install Apache, because I can’t cope with it under heavy loads.
//
If it were possible to upgrade php-fpm to 5.6 (if it exists), I'd be happy.