Answers for "change php version 8 to"

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

update php version windows

Take a backup of your htdocs and data folder (subfolder of MySQL folder), reinstall upgraded version and replace those folders.

Note: In case you have changed config files like PHP (php.ini), Apache (httpd.conf) or any other, please take back up of those files as well and replace them with newly installed version.