change php version ubuntu from 8.0 to 7.4 code example

Example 1: change php version ubuntu

//In ubunutu
Default PHP 7.1 is set on your system and you need to switch to PHP 5.6

$ sudo a2dismod php7.1
$ sudo a2enmod php5.6
$ sudo service apache2 restart
  
sudo update-alternatives --set php /usr/bin/php5.6

Example 2: ubuntu 16 upgrade php 7.0 to 7.4

sudo apt install -y php7.4 php7.4-cli php7.4-common php7.4-fpm

Example 3: how to change php version 8 to 7.1 in ubuntu 20.04

$ sudo apt install python-software-properties
$ sudo add-apt-repository ppa:ondrej/php