Downgrade php 7.2 to 7.1 in Ubuntu 18.04 LTS

gistfile1.txt

sudo add-apt-repository ppa:ondrej/php
sudo apt-get update
sudo apt-get install php7.1
sudo apt-get install php7.1-cli php7.1-common php7.1-json php7.1-opcache php7.1-mysql php7.1-mbstring php7.1-mcrypt php7.1-zip php7.1-fpm php7.1-intl php7.1-simplexml
sudo a2dismod php7.2
sudo a2enmod php7.1
sudo service apache2 restart
sudo update-alternatives --set php /usr/bin/php7.1
sudo update-alternatives --set phar /usr/bin/phar7.1
sudo update-alternatives --set phar.phar /usr/bin/phar.phar7.1 
sudo update-alternatives --set phpize /usr/bin/phpize7.1
sudo update-alternatives --set php-config /usr/bin/php-config7.1

it works
Thanks

Knowledge is power.
Thank you!

Worked like a charm. I had to install sudo apt-get install php7.1-dom php7.1-gd php7.1-intl php7.1-curl as well.