What is the difference between PHP versions?

PHP is the dominant programming language behind the majority of websites and platforms on the web (including WordPress).

As such, it constantly undergoes updates and improvements.
It is important to keep your PHP version up to date to ensure that your website is as fast and secure as possible. As far as the PHP code is concerned however, websites can still have other vulnerabilities.

There are three main factors in determining which PHP version to use on your websites:

  • The requests-per-second performance of the website/s running the PHP code (more is better)
  • The memory usage demands of each PHP version (less is better)
  • The future technical support those versions will offer (or not)

Factor 1: Evaluating Requests-Per-Second Speed

Here are the results of our own recent WPX Hosting speed tests on the different PHP versions (higher is better);

The speed difference between PHP 5.6 and PHP 7.0 is very significant; a 150% increase in requests per second.
The end result for you, if using PHP 7.X, is a much faster loading website.

Factor 2: Memory Usage

Here are the results of our own recent WPX Hosting PHP memory usage tests (lower is better);

Though the improvement in memory usage is not as significant as the speed increase, it is still a very healthy 25%.
Let’s examine the support next.

Factor 3: Future Support

The chart below shows the planned support timelines on the existing PHP versions and their statuses (courtesy of php.net):

As seen above, PHP 5.3, 5.4, 5.5 are already past the period for active support and critical security fixes. PHP 5.6’s active support finishes at the end of 2016.

This means that PHP 7.X will be the only version fully supported for 2017 and onwards. WordPress also recommends updating your PHP to at least 7.0!

With all this in mind, the decision to upgrade your sites to PHP 7.X should be an easy one.
If you’d like to know more about upgrading the PHP version of your website, you can read our article or ask us to do it for you!

Be sure to check that your websites are running on PHP 7.X. If you encounter any problems, revert to your previous PHP version and let us know!

If you get stuck with any function discussed here, please contact WPX Support via live chat (use the bottom right hand widget!) and they will usually respond and help within 30 seconds or less.