How to install PHP 7.x as PHP-FPM & FastCGI for ISPConfig 3.1 with apt on Debian 8 and 9

https://www.howtoforge.com/tutorial/how-to-install-php-7-for-ispconfig-3-from-debian-packages-on-debian-8-and-9/?lipi=urn%3Ali%3Apage%3Ad_flagship3_feed%3B%2FwhvEjEgRhisaaV5VB6iug%3D%3D

available now. PHP 7.1 is the next generation of the PHP programming language, it is up to 2 times faster than PHP 5.6 and 14 times faster than PHP 5.0 according to the release notes. The new PHP version is not 100% compatible with PHP 5.x as some deprecated API’s have been removed.