sudo apt-get update
sudo apt-get install -y apt-transport-https curl
curl https://packages.sury.org/php/apt.gpg | sudo apt-key add -
echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/php5.list

sudo apt-get update
sudo apt-get install -y php5.6
php -v

sudo update-alternatives --config php