How the WordPress PHP Version Checker Works

The PHP Version Checker asks WordPress.org whether this PHP version still sits within the current core support window. It is part of the WordPress.org Ops cluster.

Use it alongside Check PHP before a core update and the Version Checker when evaluating whether your hosting environment is ready for a WordPress upgrade.

The serve-happy endpoint

WordPress.org exposes core/serve-happy/1.0/?php_version={version}. This is the same API that wp-admin uses to show the “Your PHP is outdated” admin notice in Dashboard → Updates. It returns:

{
  "recommended_version": "8.1",
  "minimum_version": "7.4",
  "is_acceptable": true,
  "is_supported": false,
  "is_secure": false,
  "is_latest": false
}

The four boolean flags mean:

is_acceptable being true is the minimum bar — WordPress will not refuse to run. is_supported and is_secure going false means php.net has stopped releasing patches for that version, which means any PHP-level CVE found after that date will never be fixed on your host.

What Tools.town shows

The checker renders a verdict badge and a detail table:

Verdict:

• Acceptable — all four green signals. PHP is current, supported, and recommended.
• Acceptable (aging) — is_acceptable is true but is_supported or is_secure is false. WordPress will run, but the PHP version has reached or passed end-of-life. Plan to upgrade.
• Not recommended — is_acceptable is false. WordPress may still technically run on some PHP versions that fail this flag, but you are outside the supported window. Upgrade PHP before the next core update.

Below the verdict you see the recommended version, the minimum version, and a plain-language explanation of which support tier your version is in.

Quick reference: PHP version support tiers

Dates are approximate. Check php.net/supported-versions for the authoritative current state. The WordPress.org recommended version lags php.net slightly — WordPress core needs time to test and declare compatibility before bumping the recommendation.

What it is not

Not a probe of your host

The checker does not SSH into your server, query phpinfo(), or hit a URL on your domain. You type the version number yourself. The checker then asks WordPress.org whether that version is in the support window.

If you are unsure what PHP version your site actually runs:

• phpinfo() — create a file with <?php phpinfo(); in your web root, visit it, and find the PHP version at the top. Delete the file immediately after.
• WP-CLI — wp --info prints the PHP version used by WP-CLI, which is usually the same as the web PHP if they use the same interpreter.
• php -v in a shell session — accurate if the shell uses the same PHP binary as PHP-FPM or mod_php for your vhost.
• cPanel / hosting panel — usually shows the selected PHP version for your account. Note that some panels show the default; a .htaccess or user.ini override may change it for your specific domain.

Not the plugin directory’s requires_php field

Each plugin on WordPress.org can declare its own requires_php in the readme. That field is entirely separate from the serve-happy endpoint. A plugin that requires PHP 8.0 will refuse to activate on PHP 7.4 even if WordPress core itself still accepts PHP 7.4.

To check a plugin’s PHP requirement, use the Plugin Analyzer — the Overview tab shows requires_php from the listing.

Not a test that your theme or plugins are PHP 8.x-compatible

Serve-happy says “WordPress core works on this PHP.” It says nothing about whether your specific combination of theme and plugins will have PHP 8.x deprecation notices, TypeError exceptions from strict type changes, or fatal errors from removed functions. That requires testing in staging.

Pre-update workflow

Before clicking Update in wp-admin Dashboard → Updates, run this sequence:

1. Find your PHP version — use one of the methods above.
2. Run the PHP Version Checker — confirm is_acceptable is true and read the support tier.
3. Run the Core Version Checker — confirm the new WordPress release you are updating to, and note its PHP minimum (requires_php in the release details).
4. Check must-have plugins — for each critical plugin, run the Plugin Analyzer and note requires_php. If any of them require PHP 8.0 and you are on 7.4, the plugin update may fail or the plugin may deactivate.
5. Test in staging — for any PHP upgrade, spin up a staging environment and verify nothing breaks before touching production.

Pair with the Version Checker

The WordPress Version Checker tells you whether your current WordPress is up to date and shows the PHP and MySQL minimums for the current release. Running both tools together gives you the full picture: is your PHP acceptable for WordPress, and is your WordPress current relative to what WordPress.org offers?

They live side by side in the WordPress.org Ops cluster. Use-case walkthrough: Check PHP before a core update.