WordPress Compatibility with PHP 8

PHP 8 and WordPress compatibility with heart icons

You should upgrade your PHP version to 8 or later on your WordPress website. Make sure to first test it out in a staging environment, so you are sure everything works as expected. Some older plugins, themes, or code changes might not be compatible with PHP 8.

Developers and those interested in web development and design will be pleased to know that PHP received a significant update at the end of 2021. However, many of you might be hesitant about whether you should upgrade your website to this latest version, and that is reasonable and understandable.

PHP8, which is the newest version of PHP, has a lot to offer in terms of additional functionalities and performance improvements. Considering that WordPress plug-ins and WordPress core are very sensitive in their compatibility with the latest software version, the answer on whether or not to move your website will not always be clear-cut.

In this post, you will learn the most significant and newest modifications and features of PHP 8 before jumping to this version.

Is WordPress 6 Compatible with PHP 8?

With this latest update, many of you might ask if PHP 8.0+ and WordPress 6.0+ are compatible. The simple answer to that is yes. Generally, WordPress is compatible with this latest update. However, it is also worth noting that using PHP 8.0+ with WordPress 5.6 or higher is the only way to get the most out of it. In other words, you must be running WordPress 5.6 or later to benefit from PHP 8 features.

Generally, WordPress and its plug-ins are reliant on the PHP version. As a result, compatibility issues may arise significantly if the other software has not been updated to newer versions. This is especially true when it comes to major updates like PHP 8.

It is common for new WordPress versions to be released simultaneously as significant PHP updates to ensure a smooth transition. In the most recent WordPress versions, specifically 5.6, work has been done to make this possible. However, version 5.6 is developed to be beta-compatible for the time being, according to WordPress developers.

WordPress 5.6 and later versions are rigorously tested and found to be compatible with PHP 8. However, there is still a chance that the core of WordPress has problems. Therefore, the developers can’t promise that everything will work as expected.

In addition, only the WordPress core is affected by this upgrade. This shows that it may take a few more time to release the latest versions of all the third-party themes and plug-ins.

Should You Upgrade To PHP 8?

2021 has been an exciting year for many PHP programmers and their creations. PHP 8 will be the language’s next major version in 2020. This latest PHP version has many new features and performance improvements that will most likely bring positive changes.

In this situation, you might be asking yourself what’s the best way to respond to this. And you will begin questioning yourself and your co-programmers if it is worth upgrading to PHP 8 or waiting for the following versions.

The simple answer is yes. And this is common knowledge among the PHP community. After all, using the newest PHP versions, libraries, and frameworks behind it makes it simpler to monitor the codebase and add new features.

The code execution speed of PHP 8 will improve in the following years. Many PHP developers suffer from faulty comparisons, which results in unusual behavior and problems. As a result of these improvements, there has been a significant boost in the efficiency and speed of the platform. Because of that, it is now possible to compare non-numeric strings and numbers.

When Should You Not Upgrade to PHP8?

The switch to PHP 8 is one of the significant paradigm changes in PHP’s history. However, deciding whether or not to upgrade to this latest version might be tricky. This is because there is a high possibility that many WordPress site developers and owners may face short-term difficulties.

However, its long-term advantages are also considerable. After all, your website’s themes and plug-ins should be evaluated or updated for WordPress PHP8 compatibility, and any that are not should be replaced. The moment has come for website developers to begin testing their dependencies and code on PHP 8.

Despite the many advantages of upgrading to PHP 8, some instances will make you think again about upgrading. In line with that, you may want to know when you should not upgrade to PHP 8.

Web application programming languages other than PHP are simpler to learn and use. As a result, many new programmers start using Python before going on to PHP. PHP is now the most popular web development platform, but this is about to change.

As the number of PHP specialists shrinks, the price of PHP-based goods will likely climb because fewer rookie developers can provide fundamental abilities at a reasonable price, which is a contributing factor.

Aside from declining popularity, concerns regarding the security of PHP-based products have remained throughout the years. Open-source software, such as PHP, means that anybody may find any security flaws it has with access to the code.

A malicious programmer might exploit these vulnerabilities while being repaired in the latest programming language versions. Since the open-source paradigm is accountable for this problem, it could just as well be extended to other open-source technology.

How Do I Know That My Theme And Plug-ins Are Compatible With PHP8?

The best and easiest way to know if your plug-ins and theme are compatible with this latest PHP version is by using a WP Engine PHP Compatibility Checker.

Using this plug-in, you may discover whether your WordPress file system’s plug-in code and theme are incompatible with one another. The faulty code and its incompatibility with the PHP version will be shown. This tool will give you some recommendations about the plug-ins that are compatible with the most current version of PHP and WordPress.

Since it does not run your theme or plug-in code, this tool cannot uncover runtime compatibility issues. Code linting is not perfect, so bear that in mind. Inability to detect redundant code paths that may be used backward compatibility may result in false positives from this plug-in.

However, it can be a great tool to check if your themes and plug-ins are compatible with PHP 8. But this does not mean you should rely on it. The better way to check compatibility is to hire a professional WordPress developer to help you with it.

What Will I Benefit From WordPress From Upgrading To PHP8?

Using PHP 7.4 beyond November 2022 will no longer be maintained by the PHP community, which is a solid persuasion to use PHP 8. Even if you don’t need it, upgrading to PHP 8 will provide several benefits, and some of them are the following:

Better Performance

One of the latest features of this latest version is the JIT (Just-In-Time) compiler, which accounts for most of the performance increase.

JIT is a new feature in PHP 8 which enhances the development process of PHP code, resulting in an increased application speed. As a result of this redesign, it is feasible that more sophisticated apps may run faster.

Related reading: Things that Really Makes a WordPress Website Fast

New Array Of Functions

Many new functions are being introduced to make manipulating arrays easier for those of us who spend our days knee-deep in them. To find out whether an array is associative or just a list array, you can use the method ‘array is list’.

PHP 7.4 only allows the spread operator to unpack numeric-keyed arrays. However, arrays containing keys may be unpacked using the same operator in PHP 8 and later.

Union Types 2.0

Thanks to union types, developers may specify a variable in many kinds. Until recently, PHP doc annotations could only define union types.

For the first time, function signatures can include union types. Developers no longer need to use inline documentation. The syntax might be used to describe it differently.

Constructor Property Promotion

For developers, PHP 8’s new Constructor Property Promotion function will provide them with an updated and more concise syntax. The primary goal of this improvement is to streamline and expedite the registration process for real estate.

To utilize attributes with objects in the present version, they must be repeated numerous times. The property’s name must be included in the property declaration, constructor arguments, and property assignments. For classes with a high number of features and long names, this method is useless.

The Constructor Property Promotion upgrade will help developers in their marketing efforts. Value objects are easier to understand and less prone to implementation problems when there is less boilerplate code.

Attributes v2

Analyzing characteristics or annotations on database objects, components, and files is possible. For the time being, classes and functions can only have doc-comment tags and declarations.

Code declarations in PHP 8 will provide class, property, function, and method verification. The tags mentioned above are used to precede declarative assertions. A doc-block comment may occur before or after one of them.


The PHP development community is excited to see what PHP 8 offers in terms of speed and usability. As far as new features go, the JIT compiler is the most anticipated. Further support for attribute types and the OPcache extension are some of the much-awaited new features.

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