title: Make PHP7 and PHP 8 live together
body: <p>Make PHP7 and PHP 8 live together</p>
  <p>I've upgraded from PHP 7 to PHP 8. As it's usually the case with PHP, I still have php7.4 in <code>/usr/bin</code> (alongside with php8.0). But, when I run the <code>php -v</code> command, it answers php8.0.</p>
  <p>Since then, when trying to install software (for example Docker and VirtualBox), I get the error message <code>php7.4-fpm.service: Failed with result 'exit-code'</code>, followed by <code>Failed to start The PHP 7.4 FastCGI Process Manager</code>. It seems therefore that I need php7.4 to run to install such applications.</p>
  <p>But I use PHP 8 functionalities to code a website and therefore don't want to get back to php7.4</p>
  <p>Is there a way to use php8.0 and php7.4 at the same time? I could make PHP 8 work on a virtual machine but it's quite heavy.</p>
  <p>I'm on Ubuntu 20 (but I'm not sure that this problem is OS-specific).</p>
  <p>Zlotz</p>