PHP 7 is the fastest PHP version yet. Simply changing the PHP version to 7 can make your Joomla site run 50% faster or more.
We get questions often about how to upgrade to a new PHP version, so we figured we should write a short tutorial for it. This tutorial will explain how Joomla interacts with PHP and how to update to PHP 7.
It's written at a beginner level and doesn't get into too much technical jargon - just enough to understand the process.
Joomla and PHP
Using PHP in Joomla allowed Joomla's developers to dynamically generate HTML, interact with a database, and preform other complicated processes.
Joomla, however, doesn't come installed with PHP. It uses PHP, but doesn't install it. Instead, PHP is installed on the server, usually run by hosting companies. So Joomla is dependent on having a server environment that installs and processes PHP requests.
Step #1. Update to Joomla 3.9
Some older versions of Joomla (before Joomla 3.5) do not support PHP 7. However, newer versions of Joomla has built-in compatibility with PHP 7. So in order to utilize it, first update to Joomla 3.9.
Step #2. Update extensions
After updating your Joomla version, update your extensions too. This will mitigate issues and ensure compatibility.
Step #3. Ask your host to perform the update to PHP 7
As explained in the first section, PHP is installed and run on the server. Therefore, in order to update PHP, it has to be done at the server level. And server set ups vary from company to company.
As a result, by far the easiest approach is to ask your hosting company's support to do it for you. Most hosts will be able to perform the update for you quickly. Any others will likely provide documentation for their specific setup.
If you encounter any issues after updating, you can ask them to revert to your previous PHP version. It's a simple change so you can go back and forth.