What Is PHP, and Why Does Your Website Need to Keep It Updated?

You may have heard PHP mentioned in the news recently, following the discovery of some security vulnerabilities affecting websites around the world. But what exactly is PHP, what does it do, and why does keeping it updated matter for your website?

PHP is a programming language that works behind the scenes on your WordPress website. It’s responsible for much of the functionality you rely on every day, from displaying pages and retrieving content to processing contact forms and handling information. It’s not something you normally need to think about, but it’s an important part of keeping your website running.

Why do PHP versions change?

Like any software, PHP is regularly updated to improve security, performance and compatibility with newer technology. When your website was originally developed, it was built to work with a particular version of PHP that was appropriate at the time.

As newer versions are released, older versions gradually reach the end of their supported lifespan. PHP versions typically receive two years of active support, followed by two years of security support. After that, they reach what’s known as end of life, meaning the PHP developers no longer provide updates or security fixes for that version.

This doesn’t mean your website suddenly stops working. In fact, websites can continue running perfectly well on older PHP versions for years. However, it does mean that any newly discovered security vulnerabilities may remain unpatched, and compatibility with newer WordPress updates and plugins can become an issue.

What happens if my website is using an older version?

If your website is working normally, there’s no immediate reason to panic. Using an older PHP version doesn’t automatically mean your website has been compromised or that something is going to break. However, there are some important considerations.

The main concern is security. Once a PHP version is no longer supported, vulnerabilities discovered in that version won’t receive official fixes. This can increase the risk of security problems, particularly as time goes on.

Compatibility is another consideration. WordPress, themes and plugins are regularly updated, and newer versions may eventually require a more recent PHP version. Staying on an outdated version can therefore limit your ability to keep other parts of your website updated.

There are also potential performance benefits. Newer PHP versions often include improvements that allow websites to process requests more efficiently, although the actual difference will depend on the website itself.

Why can’t I just update PHP to the latest version?

In some cases, updating PHP is straightforward. However, websites are made up of several components, including WordPress, the theme, plugins and sometimes bespoke functionality. All of these need to be compatible with the version of PHP being used.

A website developed years ago may contain code that was perfectly valid at the time but isn’t compatible with newer PHP versions. Similarly, older plugins that are no longer maintained can cause problems when PHP is upgraded.

Depending on the website, some testing or development work may be needed to ensure everything continues functioning correctly.

The goal isn’t necessarily to install the newest version immediately, but to move to a supported version that’s suitable for your website.

What about the recent PHP security issues?

In October 2026, two serious security vulnerabilities were identified in PHP, affecting a range of versions. Security fixes were released for supported PHP versions, and hosting providers needed to take action to protect affected websites.

These vulnerabilities weren’t exclusive to older PHP versions, but they highlighted the importance of keeping the underlying technology updated and supported. Even a website that appears to be functioning perfectly can be affected by security issues that aren’t immediately visible.

Using a supported PHP version means security updates remain available when vulnerabilities are discovered. Once a version reaches end of life, that official protection is no longer provided.

Does my website need updating?

Not necessarily. It depends on the PHP version your website is currently running, whether it’s still supported and whether the relevant security updates have been applied.

A website using an older but supported version may be perfectly fine for the time being, particularly if an upgrade would require additional compatibility work. However, if your website is using a version that has reached end of life, we’d recommend reviewing it and planning an upgrade.

How can Eldo help?

We review PHP versions across the websites we host and contact clients where we recommend an upgrade.

Every website is different, so upgrading PHP involves checking compatibility with WordPress, the theme, plugins and any bespoke functionality, as well as testing the website to make sure everything continues working correctly.

Older websites may also require additional development work to resolve compatibility issues before they can safely move to a newer PHP version. We explain what’s required and why, along with any costs involved, before carrying out the work.

An outdated PHP version doesn’t mean your website is broken or that you need a new website. It’s simply something that needs reviewing as part of keeping your existing website secure, compatible and running reliably.