PHP 8.0 is set to be released on November 26, 2020. As the programming language powering WordPress sites, PHP’s latest version offers new features that developers will find useful and improvements that promise to greatly enhance security and performance in the long run. It also fully removes a number of previously deprecated functions. PHP 8 is a massive change from previous versions.
In this article, we hope to provide insights detailing what this means for WordPress site owners, including recommended adoption strategies.
Should I upgrade right away?
No. The upcoming major version of WordPress, 5.6, is intended to be “beta compatible with PHP 8” according to the developer chat for WordPress. Bugs may still occur for some time, even without the presence of additional plugins or themes. WordPress has called for additional testing with PHP 8 in order to find and fix as many remaining bugs as possible.
Many plugin developers working to ensure that their plugin is compatible with PHP 8 in a variety of environments. Upcoming versions will offer a level of partial support, though most have additional testing planned to reach full compatibility.
A vast number of WordPress plugins and themes will not be immediately compatible with PHP 8. Those that do not run into fatal errors during normal usage may still show unexpected behavior for some time.
What breaking changes does this include?
Some developers have long argued that PHP is insecure by default. While this is up for debate, it’s true that versions of PHP prior to PHP 8 are more fault tolerant and try very hard to ensure that code will run even if minor errors are present.
PHP 8 uses much stricter typing than previous versions. Many built-in functions are now pickier about the input they accept, and PHP 8 itself is more stringent about how input is passed to functions. Issues that previously resulted in notices now result in warnings, and issues that previously resulted in warnings now result in errors.
In other words, PHP 8 is not as lenient as previous versions. It will not try quite as hard to make code work no matter what.
What performance changes are coming?
One potentially exciting feature coming to PHP 8 is JIT, or “Just In Time” compilation. PHP is an interpreted language, meaning that it is translated into machine code as it runs. JIT keeps track of code that’s frequently used and attempts to optimize the machine code translation so that it can be reused. This can result in a massive performance improvement for specific functionality.
For the time being, however, the actual performance improvement for web applications such as WordPress is minimal, and it will take a long time before the average WordPress user or developer reaps the benefits of this new feature.
The transition to PHP 8 is one of the broadest and most impactful changes the language has ever seen. While it will be worth it in the long run, WordPress site owners and developers may find problems short term. If you’re a website owner, start keeping a watchful eye on which of your plugins and themes are being updated or tested for compatibility and make a plan to replace the ones that aren’t. If you’re a developer, start testing your code and any dependencies on PHP 8, if you’re not already, and start making a plan to fork or replace any libraries that aren’t being updated. The WordPress ecosystem has been through difficult transitions in the past, and our open-source community has always grown and adapted.