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WordPress PHP Compatibility Guide

by on August 15, 2024
Illustration of PHP and Checkmarks

PHP is the backbone of WordPress, serving as the primary programming language that powers its core functionality, themes, and plugins. WordPress regularly updates its PHP version requirements to maintain optimal performance, security, and stability for the websites built on its platform.

At the time of writing this article, the latest major version of PHP is 8.3. The latest WordPress release of 6.6 recommends using PHP 7.4 and newer, but this WordPress release can work with PHP versions up to 7.2.24.

It’s important to note that PHP versions older than the recommended minimum have reached their End of Life (EOL) and negative ramifications can occur, which we will cover later in this article.

This guide explains PHP compatibility in WordPress, breaks down the latest PHP versions, explains what the WordPress 6.6 update means for PHP requirements, and gives you the lowdown on handling these technical aspects. By the end, you’ll have a solid grasp of PHP’s role in your WordPress site and know how to fine-tune it for performance and security.

Understanding the Different PHP Versions

PHP is an open-source community project with its own release schedules independent of WordPress.

PHP versions are split into three categories of support:

  • Active support: These versions are still being worked on, and fixes for security issues and bugs are regularly released. These are currently versions 8.2 and 8.3.
  • Security fixes only: These are slightly older versions where only the most serious security issues get fixed. This is where version 8.1 is.
  • End of life: Releases that have reached EOL status are no longer supported. Anyone on such a version is vulnerable to security risks and performance issues, and should strongly consider updating to a newer release as soon as possible. These are versions 8.0 and older.

You can still find every version of PHP ever released for download from the official website, but you shouldn’t use any versions that are past their End of Life on a live website. Always utilize the latest versions where possible, and never use PHP versions that are no longer receiving security fixes.

Here are some important details on the most recent PHP versions:

  • PHP 8.1, 8.2, and 8.3 are the latest major releases of PHP, each bringing performance improvements and new features.
  • PHP 8.1 introduced enumerations, fibers for concurrent programming, and pure intersection types.
  • Version 8.2 added read-only classes and null, false, and true as stand-alone types.
  • Version 8.3 release introduced typed class constants, the #[\Override] attribute, and a json_validate() function.

The allure of the latest release is undeniable, but it’s often necessary to wait until the kinks are ironed out as third-party developers catch up. Luckily, this usually doesn’t take long, and you should ideally never be more than two major releases behind.

PHP Compatibility for WordPress 6.6

Unlike with PHP, WordPress only maintains official ongoing support for the latest major release. Older versions may or may not be supported.

WordPress 6.6 “Dorsey”, the latest release, was released in mid-July 2024. This release is generally compatible with the latest versions of PHP discussed above, save for some plugins and themes pending updates.

While WordPress recommends using PHP 7.4 or higher and maintains compatibility with up to version 7.2.24, updating to the latest PHP release can significantly improve security and performance.

Newer versions often run faster and include built-in protections against common vulnerabilities. However, staying with older, still-supported versions might be necessary to stay compatible with specific plugins or themes.

The choice comes down to your preferences and current setup, but you shouldn’t use a version that’s past active support. Because WordPress only guarantees active support for the latest release, that’s the one you should always aim to run.

The next section will help you achieve this goal.

How to Update PHP for WordPress Websites

Updating your site’s PHP version is vital for maintaining security, speed, and compatibility. Outdated versions are vulnerable to attacks, lag in performance, and may clash with newer themes and plugins.

Step 1: Validate Your Current PHP Version

To check what version of PHP you’re currently on from the admin dashboard, go to Tools > Site Health > Info. Scroll down to the Server section and expand it to reveal your PHP version.

Checking PHP Versions Inside WordPress
Checking PHP Versions Inside WordPress

If you find you’re not running the latest version of PHP, you should update it immediately.

Step 2: Create a Backup of Your Website or Blog

Before getting started, create a backup of your site just in case something goes wrong. If your hosting provider doesn’t offer backups as part of its services, you can use plugins like UpdraftPlus to create a full backup of your site. Just make sure you capture your database, plugins, themes, and media files.

Step 3: Test Changes in a Staging Environment

Try out the new version in a staging environment first, rather than the live website. There’s more information about this later in the article, but in a nutshell, it’s the most reliable way to check for compatibility between the new PHP version, WordPress, and your installed plugins and themes. Managed WordPress hosting providers like Pressable offer staging environments for this reason.

Step 4: Update the PHP Version

When you’ve verified that your site works with the new version, just log into your hosting control panel and find the built-in PHP manager. The exact steps will vary between control panels but are broadly similar. For example, in cPanel, it’s under Tools > Software > MultiPHP Manager. In Pressable, it’s under Overview > PHP Version, as shown below:

Changing PHP Versions in Pressable's Dashboard
Changing PHP Versions in Pressable’s Dashboard

Updating PHP through Pressable.

The process is this easy because any decent hosting provider should offer its customers access to the latest version of PHP for them to switch to. If not, you might have to contact them directly to request it.

Step 5: Test Website Functionality and Look for Issues

After the update, test the live website’s functionality in both the front and back-end to see if everything works as intended. Make sure you review common WordPress functions, as well as, plugin features.

Troubleshooting PHP Updates

Sometimes, updating to the latest version of PHP can introduce issues to your site, but you can usually resolve them by:

  • Clear your cache to ensure your site is using the new PHP version.
  • Check .htaccess files for rules that might be forcing an older PHP version.
  • Review error logs to identify specific PHP errors and compatibility issues.
  • Temporarily reverting to the previous PHP version while troubleshooting if needed.
  • Contact your hosting provider for assistance with server-side changes if problems persist.

Many PHP issues stem from compatibility problems with themes or plugins. The best way to prevent these is by testing updates in a staging environment before applying them to your live site.

Checking PHP Compatibility

When it comes to updating PHP, compatibility issues with themes and plugins are often the main culprits behind functionality hiccups. But don’t worry – there are ways to make sure your site plays nice with the latest PHP version before your audience ever sees a problem.

You might have heard about tools like the PHPCompatibilityWP that can scan your WordPress setup and flag potential compatibility issues. Many website owners find these tools helpful as a first step.

However, while these tools can offer useful insights, they’re not foolproof. They might raise false alarms or miss some tricky compatibility issues. The reality is that no automated tool can fully capture the intricacies of a live WordPress site.

That’s why creating a staging environment is your best bet. It’s like having a dress rehearsal for your PHP update. You get to see how the new version interacts with your unique mix of themes, plugins, and custom code, all without risking your live site.

With a staging environment, you can:

  • Spot compatibility issues in real-world conditions.
  • Put your site’s critical functions through their paces.
  • Iron out any kinks before they affect your visitors.
  • Feel confident about the update process.

Everyday Site Maintenance for PHP Problem Prevention

Keeping your WordPress site in top shape isn’t just about reacting to issues – it’s about preventing them.

Here are some best practices for keeping your site running smoothly:

  • Stay on top of updates: Keep WordPress core, themes, and plugins current. These updates often include compatibility improvements for the latest PHP versions.
  • Back everything up: Before any update, always create a full site backup. It’s your safety net if things go sideways.
  • Keep your code clean: If you’re using custom code, make sure it follows WordPress PHP Coding Standards. This helps prevent conflicts with core WordPress functions and makes future updates smoother.
  • Test in staging: Use a staging environment to test updates and changes before they hit your live site.
  • Monitor and debug: Tools like Query Monitor can help you spot PHP errors and performance issues early. Regular check-ups can save you from bigger headaches down the line.
  • Lock it down: Implement security measures like firewalls and regular scans. They help protect your site from vulnerabilities that could be exploited through PHP.

Keep Your Website Up to Date With Pressable

Keeping your WordPress website on the latest supported PHP version lets you maintain security, performance, and compatibility. While updating PHP can seem intimidating, it’s fairly simple and it is an essential part of site maintenance.

It’s advisable to use a staging environment to test PHP updates before applying them to your live site. This allows you to identify and resolve potential compatibility issues with your themes, plugins, and custom code in a safe environment.

Pressable gives you easy access to staging environments where you can run comprehensive tests before committing to PHP updates.

Take the next step in optimizing your WordPress site’s performance and security. Get started with Pressable today and plan your update strategy!

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