Установите PHP 7.1 на Ubuntu 18.04
sudo apt install php7.1 php7.1-common php7.1-opcache php7.1-mcrypt php7.1-cli php7.1-gd php7.1-curl php7.1-mysql
Itchy Impala
sudo apt install php7.1 php7.1-common php7.1-opcache php7.1-mcrypt php7.1-cli php7.1-gd php7.1-curl php7.1-mysql$ sudo add-apt-repository ppa:ondrej/phpsudo apt install software-properties-commonsudo add-apt-repository ppa:ondrej/php