This is another post in my “why I love open source software” series.
What is PHP?
PHP is software that runs in the background on the hosting server. Joomla is written in PHP and the current version of Joomla (3.9.x) will work on PHP 5.6. Wordpress, Drupal, Magento, and other popular open source software is also written in PHP. Generally, the servers we use with 'cPanel' are configured as a "LAMP" stack - stands for Linux (Operating system), Apache (web server), MySQL (database server), and PHP (programming language used in Open Source packages like Wordpress, Drupal, Joomla, etc.)
Perhaps a good comparison is if the "LAMP" stack is a car, the CMS (Wordpress, Drupal, Joomla) is like the tires and steering wheel, and PHP is the drivetrain.
My Joomla Site is Already Patched. Do I also need to update PHP?
The misleading part about the error message is when they say that PHP 5.6 no longer receives official security updates by its developers. This is true, however, the part that they’re not telling you is that hosting companies are allowed to support older versions of PHP on their own. It’s open source software! Nobody can tell you what to do with it.
So, what happens is the PHP development team says that they are going to release a new version and stop updating the older versions. So most hosting companies, and software teams like Joomla (and Drupal and Wordpress) will also adapt their software to the newer PHP version. However, the hosting companies still have hundreds and thousands of older sites from existing clients on their servers. If they stop supporting the old version of PHP, they could potentially lose customers because all of their sites might crash and they’ll potentially switch hosting companies. So rather than lose money, the hosting company will ask one of their technicians to apply a custom patch or customization to the older PHP version so that their servers still support it and their clients stay happy.
I’m not trying to say that updating to PHP 7 is a bad idea. It’d probably make your site load a bit more quickly if you’re able to make the change. And many 3rd party plugins and extensions require PHP 7, even if Joomla itself is compatible with previous PHP versions. But it’s not worth panicking over. Since most hosting companies are still supporting at least PHP 5.4, it’s probably safe to say that PHP 5.6 will be around for quite some time.