If your website stops working after a hosting upgrade, the cause is often a PHP version change that your theme or plugins were not ready for. PHP version support on shared hosting is one of those technical topics that small business owners tend to encounter suddenly, usually when something breaks rather than before. This guide covers what shared hosting PHP versions mean in practice, what active and security support actually refer to, how to check what version you are running, what compatibility testing involves, and how to approach upgrades safely on a shared plan.
What PHP version support actually means
PHP is a server-side scripting language that powers a large proportion of websites, including most WordPress, Joomla, and custom PHP sites. The PHP project releases new versions on a structured timeline, and each version moves through two distinct support phases.
Active support means the PHP project team releases regular updates including new features, performance improvements, and bug fixes. Security support is a shorter period after active support ends, during which only security vulnerabilities are patched. Once a version reaches end of life, it receives no updates at all. Running an end-of-life PHP version means any security vulnerabilities discovered after that date remain unpatched on your server.
You can check the current status of PHP versions directly on the official PHP supported versions page. That page is maintained by the PHP project and is the most reliable reference for which versions are currently supported.
For shared hosting users in the UK, this matters because many hosting providers set a default PHP version when they first provision an account. That default may have been stable when your site was built, but it can fall out of security support while your business continues to use it without anyone noticing.
Why shared hosting makes PHP version management different
Shared hosting environments host multiple websites on the same server. The hosting provider controls the server configuration, including which PHP versions are available and what the default version is for new accounts.
This arrangement has practical implications for PHP version management. You typically cannot compile your own PHP, install arbitrary extensions, or change low-level server settings. Your control is usually limited to what the hosting control panel exposes, which is often a dropdown selector for PHP version at most.
The advantage of shared hosting is simplicity. The disadvantage is that you may not have access to granular control over PHP settings, staging environments, or rollback tools that you would have on a VPS or dedicated server.
How to check your current PHP version on shared hosting
Before making any changes, you need to know what you are currently running. There are a few reliable ways to check this on a shared hosting account.
Using a phpinfo file
Create a plain text file called phpinfo.php with the following content:
<?php
phpinfo();
?>Upload this file to your website root directory using your hosting file manager or FTP client. Then visit yoursite.com/phpinfo.php in your browser. You will see a detailed summary of your PHP configuration, including the version number at the top.
Once you have checked the information, delete the file immediately. Leaving it on the server is a security risk because it exposes detailed server configuration to anyone who visits that URL.
Through your hosting control panel
Most shared hosting providers include PHP version information in their control panel. If you use cPanel, look for the PHP Version or MultiPHP Manager icon. Plesk-based hosts usually have PHP settings under the domain or hosting settings section. Your hosting provider's documentation will have the specific steps for their interface.
Checking from within your application
If you are running WordPress, several security and maintenance plugins display PHP version information in their dashboard. This is useful if you prefer not to upload temporary files. The WordPress site health tool also shows the current PHP version and whether it meets the recommended requirements.
Understanding the PHP version lifecycle and why it matters for security
Each PHP version follows a roughly predictable lifecycle. Major versions typically receive active support for approximately two years, followed by roughly one year of security-only support. After that point, the version is end of life and should not be used on any production website.
For small businesses, the practical risk of running an unsupported PHP version is that security vulnerabilities will not be patched. If a vulnerability is discovered in an end-of-life PHP version and your site is using that version, your site becomes a potential target. The hosting provider cannot patch the PHP core if the PHP project has discontinued support for that version.
This is why checking your PHP version is part of a sensible website maintenance routine for UK small businesses. Most website owners check their content updates and plugins regularly but never look at the underlying PHP version their site is running on.
Compatibility checking before upgrading PHP
Upgrading PHP is not simply a case of selecting a newer version from a dropdown. PHP versions introduce breaking changes. Code that works correctly on PHP 7.4 may produce errors on PHP 8.0 because the newer version removes deprecated functions and enforces stricter type checking.
Before upgrading on a live site, you need to check whether your theme, plugins, and any custom code are compatible with the target PHP version.
Check plugin and theme compatibility
For WordPress sites, most plugin developers list their PHP compatibility on the plugin page in the WordPress repository. Look for the Compatibility section. If a plugin has not been tested with PHP 8.x or has known compatibility issues, that is a signal to wait for an update or find an alternative.
For custom themes or plugins developed specifically for your site, you need to review the code directly. Look for deprecated functions that have been removed in newer PHP versions. The PHP manual documents which functions are deprecated in each version.
Use a development or staging environment for testing
The most reliable way to test PHP compatibility is to create a staging copy of your website and change the PHP version there first. Many shared hosting providers offer a staging tool within their control panel. If yours does not, you can set up a subdomain and duplicate your site manually.
Once you have a staging environment, change the PHP version to your target version and run through your site's key functions. Test the homepage, contact forms, e-commerce checkout if applicable, login flows, and any custom functionality. Watch for white screens of death, error messages, or unexpected behaviour.
If you are not sure whether your current hosting plan includes staging tools, check with your provider. Some shared hosting plans include it, and others do not. If staging is not available, this is a good reason to review what your website support arrangement includes before attempting a live upgrade.
Common mistakes when managing PHP versions on shared hosting
Several recurring issues come up when small businesses manage PHP versions on shared hosting plans.
Upgrading directly on the live site. Skipping the staging test and applying a PHP version change directly to production is the most common and most risky mistake. If a plugin or your theme is incompatible, your site will break, and if you do not have a recent backup, recovery can be difficult.
Ignoring the warning about end-of-life versions. Some hosting providers send notifications when a PHP version is approaching end of life or has reached it. Ignoring these notifications and continuing to run an unsupported version creates an avoidable security risk.
Assuming the latest version is always the best choice. Newer is not always better immediately. If your theme and plugins have not been tested with the latest PHP version, running it can introduce instability. It is worth waiting a few months after a major PHP release for plugin developers to catch up with compatibility updates.
Not taking a backup before upgrading. Even with staging tests, taking a full backup before changing PHP on the live site is sensible. If something goes wrong during or immediately after the upgrade, you want to be able to restore quickly.
Forgetting to test third-party integrations. Payment gateways, email marketing tools, API integrations, and embedded scripts can all behave differently under a new PHP version. Test these specifically, not just the core site functionality.
What to do if an upgrade breaks your site
If your site stops working after a PHP version change, most shared hosting control panels allow you to revert to a previous PHP version. Look for the PHP version selector in your control panel and change it back to the version that was working.
Before changing back, check whether your hosting provider retains any error logs that might indicate what caused the problem. Common causes include a plugin that is incompatible with the new version, a theme that uses deprecated functions, or custom code that references a function that no longer exists.
If reverting fixes the immediate problem, do not leave the site on an unsupported version permanently. Instead, identify the incompatible component, check whether an update is available, and plan a proper upgrade path. For WordPress sites, a regular WordPress maintenance routine helps catch these compatibility issues before they cause a live problem.
PHP extensions on shared hosting
PHP extensions add specific functionality such as database connections, image processing, or encryption. When you change PHP versions, some extensions may be enabled by default and others may need to be activated manually.
On shared hosting, you typically manage extensions through the control panel as well. Look for PHP Extensions or Select PHP Extensions in your hosting dashboard. Common extensions that WordPress and many other applications require include mysqli or pdo_mysql for database connections, gd for image handling, and curl for remote requests.
When upgrading PHP, verify that the extensions your site needs remain available and enabled. Some extensions are removed or renamed between PHP versions, which can cause previously working sites to fail after an upgrade.
How often should you review your PHP version
For most small business websites, reviewing PHP version once every six months is a reasonable baseline. Set a reminder to check the PHP supported versions page and compare it against what your site is running.
If a version you are using is within six months of losing active support, start planning your compatibility testing. If it has already reached end of life, treat it as urgent and prioritise the upgrade.
Between reviews, monitor any notifications from your hosting provider. Many hosts send automated emails when a PHP version is being deprecated on their platform, which is usually a stronger signal to act than a general calendar reminder.
When to handle a PHP upgrade yourself and when to ask for help
If your site uses a well-maintained theme and popular plugins that are already compatible with a newer PHP version, and if your hosting control panel provides a straightforward PHP version selector, you can handle the upgrade yourself with a staging test first. The process is reasonably low risk when those conditions are met.
If your site uses custom code, older premium themes that have not been updated, plugins that are no longer actively maintained, or if your hosting control panel does not give you staging tools, it makes sense to get technical help before upgrading. A small investment in a compatibility review can prevent a site outage that costs more in lost enquiries and recovery time.
If you are unsure about any part of the process, speaking to someone who has done this before is sensible. PHP upgrades on shared hosting are straightforward in simple cases but can become complicated quickly when custom code or older plugin versions are involved.
Next steps for your shared hosting PHP setup
Checking your PHP version is a small task that can prevent unexpected problems later. If you have not looked at it recently, log into your hosting control panel and see what version your site is running. Compare it against the current supported versions and plan a compatibility test if an upgrade is due.
For UK small businesses that would prefer to have someone handle the review and upgrade process, N. Cristea offers website maintenance support that includes checks on PHP version, compatibility testing, and staged upgrades where needed. You can get in touch to discuss the current setup of your site and what a sensible review would involve.