switch php versions - ubuntu

list.txt

1. (optional) install some php version:           sudo apt -y install php7.4
2. switch php version:                            sudo update-alternatives --config php
2.1. disable current version:                     sudo a2dismod php7.1
2.2. enable version:                              sudo a2enmod php7.4
3. restart apache                                 sudo systemctl restart apache2