Understanding PHP Versions and Why They Matter for WordPress

What PHP Is and How It Relates to WordPress

A quick, non‑technical explanation of PHP

PHP is the programming language that powers WordPress. If your website is a restaurant, PHP is the kitchen where the meals are cooked to order. Visitors only ever see the finished plate (the web page in their browser), but every page is prepared on the server using PHP.

When someone visits your site, your web server runs PHP scripts, pulls data from the database and then outputs HTML that the browser can display. That whole process happens in fractions of a second, every time someone loads a page.

For most business owners, the details of the code do not matter. What does matter is that:

• WordPress depends on PHP to work at all
• The version of PHP you are running affects speed, security and compatibility
• Your hosting company controls which PHP versions are available

How WordPress uses PHP to generate your pages

Every core part of WordPress is written in PHP:

• Core files handle things like logging in, managing posts, and the admin dashboard.
• Templates decide how posts, pages and archives look on the front end.
• Database queries are built in PHP to fetch content, users, orders and settings.

When a user requests /about-us/:

1. The web server receives the request.
2. PHP loads WordPress core files.
3. WordPress checks the database for the matching page.
4. PHP runs theme and plugin code to build the layout and extra features.
5. HTML is sent to the visitor’s browser.

The efficiency of this PHP process has a direct effect on how quickly your pages load. Modern PHP versions handle these operations far more efficiently than older ones, which is a core part of any serious web hosting performance features offering.

Themes, plugins and WooCommerce are all PHP too

Almost everything you install in WordPress is also largely PHP:

• Themes use PHP to generate headers, footers, sidebars and templates.
• Plugins add PHP code for forms, SEO, security, page builders and more.
• WooCommerce uses PHP for products, baskets, checkout, emails and reporting.

Each of these components often has a “minimum PHP version” they support. If your server is running an older version than your theme or plugin expects, you can see errors, broken layouts or missing functionality.

This is why PHP versions are not an abstract technical detail. They control whether your WordPress and WooCommerce stack can safely run current, supported code.

Why PHP Versions Matter for Your WordPress Site

Performance: how newer PHP makes WordPress faster

Newer PHP versions are usually significantly faster than older ones. Benchmarks often show modern versions handling 2 to 3 times as many requests per second as PHP 5.x and 50 to 100 percent more than early 7.x releases.

In practical terms, upgrading PHP can lead to:

• Faster page loads, especially under load
• Lower server CPU and memory usage
• More consistent response times during traffic spikes or marketing campaigns

This is particularly noticeable on WooCommerce stores and sites with heavy plugins such as page builders and membership systems. Efficient PHP lets your server do more with the same resources, which can sometimes delay the need for a more powerful hosting plan.

Security: what happens when PHP reaches end of life

Every PHP version has a support lifecycle. After a certain date, that version reaches “end of life” and no longer receives security updates from the official PHP team.

Running an end of life PHP version means:

• Newly discovered vulnerabilities might never be patched
• Security scanners and auditors will often flag your site as using outdated software
• Your hosting provider may eventually force an upgrade anyway, on their own timetable

Even if your WordPress core and plugins are fully updated, an unsupported PHP version underneath can still be a weak point. For sites handling customer data, logins or payments, this becomes a clear risk.

On well managed platforms, such as managed WordPress hosting with G7Cloud, PHP versions are kept within the actively supported window, reducing this exposure.

Compatibility: plugins, themes and “minimum PHP” requirements

Plugin and theme authors follow PHP’s progress. As new language features appear, they adopt them to improve performance, maintainability and security.

To do this, they set minimum PHP requirements, such as “PHP 7.4 or higher” or “PHP 8.1+ recommended”. If your site is running PHP 7.0 and a plugin now requires 7.4, you may see:

• Update blocked with a warning in the dashboard
• White screens or fatal errors if incompatible code is loaded
• Support teams asking you to upgrade PHP before they can help

The other side of compatibility is upgrading too fast without checking dependencies. Jumping from very old PHP to the newest release without testing can expose outdated plugins that still rely on removed functions. A careful upgrade path avoids both extremes.

Compliance and risk for ecommerce and sensitive data

If you run an online shop, membership site or anything involving personal data, PHP versions feed into your compliance picture.

Consider:

• PCI DSS for card payments: even with off‑site gateways, you are expected to keep your platform patched and supported.
• GDPR and data protection: using clearly outdated, unsupported software can be hard to justify if there is a breach.
• Client expectations: larger B2B customers may ask what versions you run as part of due diligence.

Being on a currently supported PHP version is a straightforward, low‑friction way to reduce risk and demonstrate basic technical hygiene.

Recommended PHP Versions for WordPress in 2025

Supported PHP versions and official WordPress guidance

The exact PHP versions supported can change during the year, so always cross‑check the current guidance on the official WordPress Hosting Handbook.

As of late 2024, WordPress core typically:

• Requires a relatively old minimum PHP (for backward compatibility)
• Recommends a much more modern PHP version for performance and security

Although WordPress can often run on older PHP, you will usually see better results by following the recommended version rather than the bare minimum.

Choosing a target version: safe defaults for most sites

For most UK business sites in 2025, a sensible approach is:

• Aim for a currently supported PHP 8.x version (not end of life, not alpha/beta).
• Avoid newly released major versions for the first few weeks on critical production sites.
• Keep development or staging environments one step ahead to test future upgrades.

This strikes a balance between stability and taking advantage of speed and security improvements. A good hosting provider will make several supported PHP 8.x versions available, so you can choose the most appropriate one for your stack.

How WooCommerce stores should think about PHP versions

WooCommerce stores are particularly sensitive to PHP versions because:

• The codebase is large and interacts with many plugins and payment gateways.
• Checkout performance directly affects revenue and abandoned baskets.
• Security and uptime are both commercially critical.

As a rule of thumb for serious shops:

• Run a currently supported PHP 8.x version that WooCommerce explicitly supports.
• Test checkout, order emails, and integrations (shipping, accounting, CRM) on staging before any PHP jump.
• Coordinate PHP upgrades with plugin and gateway updates rather than changing them at random times.

If your store is still on PHP 7.x, planning a move to a modern 8.x release should be treated as a priority improvement project rather than something to postpone indefinitely.

How to Check Which PHP Version Your WordPress Site Is Using

Check via WordPress Site Health tool

The easiest way for most site owners is via the built‑in Site Health feature:

1. Log in to your WordPress dashboard.
2. Go to Tools → Site Health.
3. Click the Info tab.
4. Expand the Server section.
5. Look for PHP version.

Note down both the major and minor numbers, for example “8.1.23”. This is the number you will compare against WordPress and plugin recommendations.

Check via your hosting control panel (cPanel and similar)

Most control panels show your PHP version and let you change it:

• cPanel: look for Select PHP Version or MultiPHP Manager.
• Plesk: check under PHP Settings for your domain.
• Custom panels: often have a “PHP” or “Runtime” section in site or application settings.

Here you can usually see which versions are available to choose from and, in many cases, set different PHP versions per site or subdomain.

Check via phpinfo or a hosting support ticket

For more technical checks you (or your developer) can:

• Create a file called phpinfo.php containing <?php phpinfo(); ?>, upload it to your site, visit it in a browser, then delete it again once you are done.
• Ask your host’s support team which PHP version is running for a particular domain.

Be careful not to leave phpinfo() files lying around, as they reveal detailed configuration information that you would not usually want exposed.

Should You Upgrade PHP? A Simple Decision Checklist

Warning signs you are on an unsafe or outdated PHP version

You should strongly consider planning an upgrade if any of the following are true:

• Site Health warns that your PHP version is insecure or outdated.
• Your host marks your PHP version as “deprecated” in the control panel.
• Plugins or themes refuse to update due to low PHP version.
• Security scans or audits flag your PHP version as end of life.

In these cases, staying where you are is a growing risk and the question becomes “how to upgrade safely” rather than “whether to upgrade at all”.

Balancing performance gains against compatibility risk

If you are on a supported, but slightly older PHP version, weigh up:

• Benefits: faster execution, better resource usage, ongoing security fixes.
• Risks: legacy plugins or code may break if they use removed features.

A staged path, such as moving from PHP 7.4 to 8.0, then to 8.1 or 8.2 after proper testing, can be more comfortable than jumping straight from 7.0 to the newest available.

Special cases: legacy code, old themes and abandoned plugins

Some sites rely on:

• Custom code from an agency that is no longer around
• Old premium themes that have not been updated in years
• Plugins that are clearly abandoned in the WordPress.org directory

Here the path forward might involve replacing or refactoring problematic components before you can adopt the newest PHP. It is important not to use this as justification to stay indefinitely on insecure versions. In such cases, a structured upgrade plan and possibly external developer help are often worth the investment.

How to Safely Upgrade PHP for a WordPress Site

Step 1: Take a full backup and know how to restore

Before any PHP change, ensure you have a complete, recent backup:

• Database (all tables)
• Files (core, themes, plugins, uploads)

Equally important, make sure you know how to restore that backup if something goes wrong. If you are not confident about your backup process, the article How to Back Up Your WordPress Site walks through practical options and tools.

Step 2: Update WordPress core, themes and plugins first

Bringing your codebase up to date before upgrading PHP reduces the chance that you will hit compatibility problems. Update:

• WordPress core to the latest stable release
• All actively maintained themes and plugins
• WooCommerce and its extensions, if applicable

If anything cannot be updated due to licence or compatibility issues, note it down. These components may need extra testing or replacement.

Step 3: Use a staging site or clone to test the new PHP version

Ideally, create a staging copy of your site on your host or a local environment that mirrors your live setup:

• Same WordPress version and plugins
• Same theme and child theme, if any
• Similar PHP configuration where possible

Switch PHP on the staging site first and run through key user journeys (see below). Fixing problems here is less stressful than debugging a live site while customers see errors.

Step 4: Switch PHP version in your hosting control panel

Once you are happy with staging tests, schedule a quiet time to change PHP on the live site:

1. Take or verify your latest backup.
2. Switch the PHP version for your domain in your control panel.
3. Clear any caches (plugin caches, server caches and CDN caches).
4. Reload a few pages while logged in and logged out.

If your host offers per‑site PHP settings and isolation, use them so that one site can move ahead without dragging others along before they are ready.

Step 5: Test key user journeys and fix common issues

After the switch, test:

• Homepage, key landing pages and navigation menus
• Login, registration and password reset
• Forms (contact, quote, newsletter signup)
• For WooCommerce: product pages, basket, checkout, payment and order emails

Keep your error logs open while doing this if possible. They are often the quickest way to spot which plugin or theme is reacting badly to the new PHP version.

Common Problems After a PHP Upgrade (and How to Fix Them)

White screen, 500 errors and PHP fatal errors

The most dramatic issues include:

• “White screen of death” (blank page)
• HTTP 500 Internal Server Error
• Explicit “PHP Fatal error” in logs or output

To troubleshoot:

• Check the site’s error logs in your hosting control panel.
• Temporarily disable all plugins via FTP by renaming the plugins folder.
• Switch to a default theme, such as Twenty Twenty‑Four, to rule out theme issues.

Once the site loads again, re‑enable plugins one by one until the error reappears. This will identify the incompatible component. For broader guidance on tackling these kinds of issues, see Top 10 Most Common WordPress Issues and How to Resolve Them.

Deprecated functions and noisy error logs

Newer PHP versions deprecate older functions. Often the site still works, but your logs fill with messages like “Deprecated: Function xyz() is deprecated”. While not immediately critical, they indicate code that will eventually need updating.

To manage this:

• Keep error reporting to logs only on production, not visible to visitors.
• Report the deprecation messages to theme or plugin authors.
• Plan code updates or replacements if the project appears unmaintained.

Page builders, WooCommerce and other plugin‑specific issues

Complex plugins such as page builders and ecommerce systems push PHP harder and are more likely to expose compatibility issues after an upgrade. Common symptoms include:

• Builder interfaces not loading correctly
• Saving content returning 500 errors
• Checkout or basket pages misbehaving

Staying fully up to date before you change PHP reduces this, but some conflicts will still occur. For example, if you use Elementor and hit 500 errors on save, the article How to Fix the Elementor 500 Error When Saving a Page covers common causes and workarounds.

When to downgrade temporarily and when to call in help

If a critical feature breaks and you cannot quickly fix it:

• Downgrade PHP one step (for example from 8.1 to 8.0) if your host allows it.
• Record the error messages, logs and affected URLs.
• Contact your hosting provider or a WordPress developer with those details.

A temporary rollback is a valid short‑term safety measure, but should not become a permanent state. Use the breathing space to plan a proper upgrade path.

How Hosting Choices Affect Your PHP Version

Shared hosting vs managed WordPress hosting for PHP updates

On low‑cost shared hosting, you may find:

• Limited PHP version choice
• Old versions hanging around because many customers have not upgraded
• Little or no guidance on when you should move to a newer PHP

By contrast, good managed WordPress hosting typically:

• Offers multiple modern PHP versions and retires insecure ones promptly
• Provides per‑site controls so you can stage upgrades
• Includes support that understands WordPress‑specific PHP issues

This can significantly reduce the amount of time you spend worrying about underlying runtime versions.

Per‑site PHP settings, isolation and performance

Being able to set PHP per site, or even per application within a site, lets you move projects forward at different speeds. For agencies or organisations running many WordPress installs, this is especially valuable.

Site isolation also helps with performance. Rather than dozens of unrelated sites sharing the same PHP worker pool, each important site can have its own tuned configuration. This aligns with the kind of web hosting performance features you should be looking for when choosing a provider.

Why server tuning and PHP‑FPM configuration also matter

PHP version is only one part of the runtime picture. How PHP is executed on the server has a big impact too. PHP‑FPM (FastCGI Process Manager) is the modern standard for running PHP efficiently, but it needs sensible settings:

• pm.max_children controls how many PHP workers can run at once.
• pm.max_requests influences worker recycling and memory usage.
• OPcache configuration determines how effectively compiled PHP code is reused.

For more advanced tuning once you are on a good PHP version, the guide How to Tune PHP‑FPM for Performance explores these topics in more depth.

PHP Version, Performance and the Bigger Speed Picture

PHP as one part of overall WordPress performance

Upgrading PHP improves the speed at which the server can generate pages, but overall performance also depends on:

• Caching strategy (page, object and browser caching)
• Database health and indexing
• Front‑end assets (CSS, JavaScript and images)
• Network latency and content delivery

Think of PHP as the engine in your car. A better engine helps, but tyres, aerodynamics and weight still matter. It is worth addressing all of these areas over time if you care about fast, reliable sites.

How caching reduces PHP load and smooths out traffic spikes

Caching reduces the amount of work PHP has to do by storing and serving pre‑generated responses. When configured well, this can:

• Serve many page views without running any PHP at all
• Keep response times stable during traffic peaks
• Lower CPU usage and reduce the risk of overload

Solutions like the G7 Acceleration Network combine edge caching and smart routing so that many visitors receive cached HTML directly from nearby locations, rather than hitting PHP and the database on every request.

Because G7Cloud’s bot protection within the G7 Acceleration Network filters abusive and non‑human traffic before it reaches PHP or MySQL, you also avoid wasting CPU on bots hammering login pages or search endpoints, which keeps performance steadier under real customer traffic.

Media and image optimisation alongside PHP upgrades

Images are often the largest part of a page’s weight. While a modern PHP version helps generate pages quickly, oversized or poorly compressed images will still slow down loading, especially on mobile.

Good practice includes:

• Uploading images at sensible dimensions rather than multi‑megapixel originals
• Using modern formats like WebP or AVIF where browser support allows
• Letting your CDN or optimisation layer handle on‑the‑fly compression

For sites hosted with G7Cloud, the G7 Acceleration Network automatically converts images to modern AVIF and WebP formats on the fly. This typically cuts image file sizes by more than 60 percent while keeping real‑world quality and requires no extra plugins or WordPress changes.

G7 Acceleration Network: caching, image optimisation and bot filtering without extra plugins

Putting it together, a modern PHP version pairs well with an edge layer that:

• Caches HTML and static assets close to visitors
• Optimises images into efficient formats automatically
• Filters bad bots and abusive crawlers before they hit the server

The G7 Acceleration Network is one practical example of this: it handles caching, image optimisation and bot filtering as part of the hosting platform, so you do not need to juggle multiple extra plugins to achieve the same effect. Combined with an up‑to‑date PHP version, this gives a solid baseline for both speed and resilience.

Making PHP Maintenance Part of Your Regular WordPress Care

How often to review PHP versions and plan upgrades

A sensible rhythm for most businesses is:

• Check your current PHP version at least twice a year.
• Review the official PHP support timeline annually and note end‑of‑life dates.
• Plan upgrades a few months before your current version is due to lose security support.

This avoids urgent, last‑minute changes driven by a host forcing you off an old version with little warning.

Linking PHP checks with your wider WordPress maintenance

PHP is only one part of a broader maintenance routine that should also cover:

• Core, theme and plugin updates
• Backups and restore tests
• Security scans and user access reviews
• Performance checks and front‑end audits

Combining these into a single scheduled task, or using a WordPress maintenance service, keeps the work predictable rather than reactive. For a wider look at this mindset, you might also find “How to Keep WordPress Secure Without Constant Firefighting” useful as a next step.

When it is time to move to a host that takes PHP seriously

Consider changing host if you find that:

• You cannot access any supported PHP 8.x version.
• Your host is very slow to offer newer versions after their release.
• Support is unable to explain their PHP roadmap or help with basic issues.

A provider that treats PHP as a core part of the service, rather than an afterthought, will make it far easier to keep your WordPress or WooCommerce site secure and performant over the long term. Exploring managed WordPress hosting with G7Cloud can be a straightforward way to reduce the day‑to‑day overhead of these tasks.

Summary: Key Takeaways on PHP Versions for WordPress Owners

PHP is the engine that powers WordPress, WooCommerce, themes and plugins. The version you run affects:

• Speed: newer PHP versions handle more requests with fewer resources.
• Security: end‑of‑life versions no longer receive fixes for vulnerabilities.
• Compatibility: modern plugins and themes often require modern PHP.
• Compliance: especially for ecommerce and data‑sensitive sites.

In 2025, most sites should be aiming for a supported PHP 8.x release, tested first on staging, with full backups in place. Upgrades are safest when paired with up‑to‑date WordPress core, themes and plugins, and when your hosting platform supports per‑site PHP versions and sensible defaults.

From there, consider PHP as one part of a bigger performance picture, alongside caching, image optimisation and protection against abusive bots. If you are ready to simplify that stack, looking at managed WordPress hosting and the G7 Acceleration Network can help you spend less time wrestling with versions and more time on your actual business.