Why Running Old (End of Life) PHP Is a Real Security Risk

Many businesses unknowingly continue running old PHP versions long after a website launches. In many cases, production sites still run exactly as they did on day one, including the PHP version.

Once that PHP version reaches end of life (EOL), it no longer receives security updates, and the security risk increases over time, even if the site still appears to work normally. This is one of the most common causes of avoidable website security issues, and it is usually fixable with a combination of planned upgrades and properly managed hosting.

The hidden risk you can’t see

Many business websites follow a “if it isn’t broken, don’t touch it” approach. If a site loads quickly, forms work, and customers are not complaining, the underlying PHP version is rarely revisited.

The problem is that stability at the surface hides technical debt underneath. When a PHP version reaches end of life, it stops receiving security fixes entirely. Any new vulnerabilities discovered after that point remain permanently unpatched. A site can look healthy while quietly becoming more exposed month after month.

Just because a website appears to function correctly does not mean it is secure.

The PHP lifecycle broken down

According to the official PHP project’s supported versions page, every PHP release follows a defined lifecycle:

• Active support: Bugs and security issues are fixed regularly.
• Security support only: Only critical security vulnerabilities are patched.
• End of life (EOL): No fixes of any kind are provided, and users are advised to upgrade as soon as possible.

Once a PHP version reaches EOL, the PHP project stops issuing security updates altogether. From that point on, any newly discovered vulnerability in that version remains unpatched unless an external vendor provides extended support.

PHP 8.0 and 8.1: a real-world warning

PHP 8.0 illustrates why EOL dates are not just theoretical. Within the first 12 months after PHP 8.0 reached end of life on November 26, 2023, CloudLinux released 13 separate CVE-related security patches for alt-php80, backporting fixes for vulnerabilities discovered after community support had ended (CloudLinux changelog).

PHP 8.1 has now followed the same path, reaching end of life on December 31, 2025. Sites that only upgrade to 8.1 are already running on an unsupported branch. To genuinely reduce long-term security risk rather than postponing it, upgrading to a fully supported version such as PHP 8.3 is the safer and more future-proof approach.

What happens if you stay on EOL PHP

Running an end-of-life PHP version is similar to running unsupported operating system software. It may continue to work, but every newly discovered flaw remains unresolved.

Known vulnerabilities affecting EOL PHP versions are publicly listed in CVE databases. Attackers actively target these versions precisely because they know fixes will never arrive unless the site owner upgrades or pays for extended support.

This exposure can lead to malware infections, injected spam or phishing content, and in some cases data breaches. On platforms such as WordPress, where PHP underpins core functionality, the impact can be severe. Beyond technical risk, unsupported software can also create compliance issues and reputational damage if a compromise becomes visible to customers or search engines.

Your two practical options

In practice, there are two realistic paths forward. Only one is sustainable long term.

Option 1: Upgrade PHP

The most secure and future-proof solution is to upgrade your application to run on a currently supported PHP version, ideally the latest stable release such as PHP 8.3.

This typically involves reviewing your codebase and dependencies, including themes, plugins, and frameworks, for compatibility. A proper upgrade is staged, tested in a non-production environment, and then deployed during a controlled maintenance window.

Upgrading returns your site to the official PHP support window, allowing your hosting platform to apply security updates safely and consistently. This remains the correct long-term approach for maintaining performance, stability, and security.

Prefer a visual explanation?

If you would rather see this explained step by step, this short video provides a clear overview of why keeping PHP up to date matters and what typically changes during a PHP upgrade:

Watch: Why updating PHP matters and how it works

Option 2: Hardened PHP via Imunify360

If an immediate upgrade is not feasible, Hardened PHP can reduce risk by applying backported security patches to selected end-of-life PHP versions. This should be treated as a temporary mitigation, not a replacement for upgrading.

Hardened PHP buys time while you plan, test, and schedule a proper migration, but it does not remove the need to move to a fully supported PHP version.

What Hardened PHP actually does

Once a PHP version reaches end of life, the PHP.net team no longer patches it. Hardened PHP, provided by CloudLinux (security features overview), addresses this gap for widely used legacy PHP branches.

CloudLinux tracks security vulnerabilities affecting these versions and backports relevant fixes so the PHP runtime continues to receive protection against known issues. From an administration perspective, the PHP engine receives security updates, while application code, themes, and plugins behave as before.

Hardened PHP does not introduce new language features, syntax changes, or performance improvements. It exists to reduce risk while a proper upgrade path is planned and executed, not to allow unsupported PHP versions to run indefinitely.

If you want a deeper explanation of how Hardened PHP fits into server-level protection, including how it works alongside malware scanning, intrusion prevention, and real-time threat blocking, see our Imunify360 for VPS anti-malware protection page for more detail.

Proactive maintenance matters

PHP end of life dates are published years in advance. Security risk increases as soon as maintenance stops, not when a site visibly breaks, so waiting for errors is the worst possible strategy.

In a properly managed hosting environment, the hosting provider maintains and updates the available PHP versions on the platform and monitors PHP life cycles in advance. On a managed VPS, the server stack, operating system, and PHP runtimes are kept up to date and supported, but it remains the responsibility of the website owner and their developers to ensure their site’s code, themes, and plugins are running on a supported PHP version.

The goal is calm, planned maintenance rather than last-minute fixes or reactive security incidents. That includes early guidance on upcoming PHP changes, safe upgrade windows, and temporary mitigations where an immediate upgrade is not yet practical.

If you are unsure which PHP version your site is running, that is the right place to start. Check it in your control panel and plan the upgrade before it becomes a security issue. If you need help understanding your options or planning a migration path, contact u>support@layershift.com</u for guidance.

Frequently asked questions

1. What does PHP end of life mean?

When a PHP version reaches end of life, it no longer receives security or bug fixes from the PHP project. Any new vulnerabilities discovered after that point remain unpatched unless you upgrade to a supported version or use extended support from a third party.

2. Is it dangerous to run an old PHP version if my site still works?

Yes. A website can continue to function normally while still being exposed to known security vulnerabilities. Once a PHP version is end of life, stability does not mean the software is secure.

3. Does upgrading PHP break websites?

Upgrading PHP can expose compatibility issues in older themes, plugins, or custom code. This is why upgrades should always be tested in a staging environment before being applied to a live site.

4. How do I check which PHP version my site is using in Plesk?

Log in to Plesk, go to Websites & Domains, select the site, then open PHP Settings. The active PHP version is shown at the top of the page. Each site can run a different version, so it is worth checking individually.

5. Who is responsible for upgrading PHP on a managed VPS?

Layershift maintains the PHP versions available on the platform and keeps the server stack updated. The website owner and their developers are responsible for ensuring their site’s code, themes, and plugins run on a supported PHP version.