This how to will enable PHP 5.6, 7.0, 7.1, 7.2, 7.3 and 7.4 to specific/desired domains.

Tutorial is for Debian and Ubuntu.

First pre-required step for Debian 9 Strech:

apt-get update
apt install apt-transport-https ca-certificates
wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
sh -c 'echo "deb https://packages.sury.org/php/ stretch main" > /etc/apt/sources.list.d/php.list'

First pre-required step for Debian 8 Jessie:

apt-get update
apt install apt-transport-https ca-certificates
wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
sh -c 'echo "deb https://packages.sury.org/php/ jessie main" > /etc/apt/sources.list.d/php.list'

First pre-required step for Ubuntu:

apt-get update
apt install apt-transport-https ca-certificates
wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg

Then in your browser go to https://launchpad.net/~ondrej/+archive/ubuntu/php/
Under Adding this PPA to your system click Technical details about this PPA, select your Ubuntu version, and two lines that you get from field box below add to /etc/apt/sources.list.d/php.list

Add php repository

sudo add-apt-repository ppa:ondrej/php
sudo apt-get update

Second pre-required step for both Debian and Ubuntu:

apt-get update
a2enmod proxy_fcgi setenvif

PHP 5.6

apt-get install php5.6-apcu php5.6-mbstring php5.6-bcmath php5.6-cli php5.6-curl php5.6-fpm php5.6-gd php5.6-intl php5.6-mcrypt php5.6-mysql php5.6-soap php5.6-xml php5.6-zip php5.6-memcache php5.6-memcached php5.6-zip
update-rc.d php5.6-fpm defaults
a2enconf php5.6-fpm
systemctl restart apache2
cp -r /etc/php/5.6/ /root/vst_install_backups/php5.6/
rm -f /etc/php/5.6/fpm/pool.d/*
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-56.stpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-56.stpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-56.tpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-56.tpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-56.sh -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-56.sh
chmod a+x /usr/local/vesta/data/templates/web/apache2/PHP-FPM-56.sh

For PHP 7.0

apt-get install php7.0-apcu php7.0-mbstring php7.0-bcmath php7.0-cli php7.0-curl php7.0-fpm php7.0-gd php7.0-intl php7.0-mcrypt php7.0-mysql php7.0-soap php7.0-xml php7.0-zip php7.0-memcache php7.0-memcached php7.0-zip
update-rc.d php7.0-fpm defaults
a2enconf php7.0-fpm
systemctl restart apache2
cp -r /etc/php/7.0/ /root/vst_install_backups/php7.0/
rm -f /etc/php/7.0/fpm/pool.d/*
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-70.stpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-70.stpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-70.tpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-70.tpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-70.sh -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-70.sh
chmod a+x /usr/local/vesta/data/templates/web/apache2/PHP-FPM-70.sh

For PHP 7.1

apt-get install php7.1-apcu php7.1-mbstring php7.1-bcmath php7.1-cli php7.1-curl php7.1-fpm php7.1-gd php7.1-intl php7.1-mcrypt php7.1-mysql php7.1-soap php7.1-xml php7.1-zip php7.1-memcache php7.1-memcached php7.1-zip
update-rc.d php7.1-fpm defaults
a2enconf php7.1-fpm
systemctl restart apache2
cp -r /etc/php/7.1/ /root/vst_install_backups/php7.1/
rm -f /etc/php/7.1/fpm/pool.d/*
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-71.stpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-71.stpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-71.tpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-71.tpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-71.sh -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-71.sh
chmod a+x /usr/local/vesta/data/templates/web/apache2/PHP-FPM-71.sh

For PHP 7.2

apt-get install php7.2-apcu php7.2-mbstring php7.2-bcmath php7.2-cli php7.2-curl php7.2-fpm php7.2-gd php7.2-intl php7.2-mysql php7.2-soap php7.2-xml php7.2-zip php7.2-memcache php7.2-memcached php7.2-zip
update-rc.d php7.2-fpm defaults
a2enconf php7.2-fpm
systemctl restart apache2
cp -r /etc/php/7.2/ /root/vst_install_backups/php7.2/
rm -f /etc/php/7.2/fpm/pool.d/*
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-72.stpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-72.stpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-72.tpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-72.tpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-72.sh -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-72.sh
chmod a+x /usr/local/vesta/data/templates/web/apache2/PHP-FPM-72.sh

For PHP 7.3

apt-get install php7.3-apcu php7.3-mbstring php7.3-bcmath php7.3-cli php7.3-curl php7.3-fpm php7.3-gd php7.3-intl php7.3-mysql php7.3-soap php7.3-xml php7.3-zip php7.3-memcache php7.3-memcached php7.3-zip
update-rc.d php7.3-fpm defaults
a2enconf php7.3-fpm
systemctl restart apache2
cp -r /etc/php/7.3/ /root/vst_install_backups/php7.3/
rm -f /etc/php/7.3/fpm/pool.d/*
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-73.stpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-73.stpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-73.tpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-73.tpl
wget http://dl.mycity.tech/vesta/php-fpm-tpl/PHP-FPM-73.sh -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-73.sh
chmod a+x /usr/local/vesta/data/templates/web/apache2/PHP-FPM-73.sh

For PHP 7.4

apt-get install php7.4-apcu php7.4-mbstring php7.4-bcmath php7.4-cli php7.4-curl php7.4-fpm php7.4-gd php7.4-intl php7.4-mysql php7.4-soap php7.4-xml php7.4-zip php7.4-memcache php7.4-memcached php7.4-zip
update-rc.d php7.4-fpm defaults
a2enconf php7.4-fpm
systemctl restart apache2
cp -r /etc/php/7.4/ /root/vst_install_backups/php7.4/
rm -f /etc/php/7.4/fpm/pool.d/*
wget https://github.com/t0rik/vesta-php-fpm-74/raw/master/PHP-FPM-74.stpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-74.stpl
wget https://raw.githubusercontent.com/t0rik/vesta-php-fpm-74/master/PHP-FPM-74.tpl
 -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-74.tpl
wget https://raw.githubusercontent.com/t0rik/vesta-php-fpm-74/master/PHP-FPM-74.sh -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-74.sh
chmod a+x /usr/local/vesta/data/templates/web/apache2/PHP-FPM-74.sh

Update for PHP 8.0

apt-get install php8.0-apcu php8.0-mbstring php8.0-bcmath php8.0-cli php8.0-curl php8.0-fpm php8.0-gd php8.0-intl php8.0-mysql php8.0-soap php8.0-xml php8.0-zip php8.0-memcache php8.0-memcached php8.0-zip
update-rc.d php8.0-fpm defaults
a2enconf php8.0-fpm
systemctl restart apache2
cp -r /etc/php/8.0/ /root/vst_install_backups/php8.0/
rm -f /etc/php/8.0/fpm/pool.d/*
     
wget https://raw.githubusercontent.com/t0rik/vesta-php-fpm-80/main/PHP-FPM-80.stpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-80.stpl
wget wget https://raw.githubusercontent.com/t0rik/vesta-php-fpm-80/main/PHP-FPM-80.tpl -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-80.tpl
wget https://raw.githubusercontent.com/t0rik/vesta-php-fpm-80/master/PHP-FPM-80.sh -O /usr/local/vesta/data/templates/web/apache2/PHP-FPM-80.sh
chmod a+x /usr/local/vesta/data/templates/web/apache2/PHP-FPM-80.sh

Now simply go to Vesta, edit WEB for desired domain and choose: Needed php version.