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Resolving PHP 8.4 Deprecated Warnings in Yoast SEO

16 threads Sep 16, 2025 Plugin → Yoast seo

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If you've recently upgraded to PHP 8.4 and are seeing a flood of deprecated notices related to the Yoast SEO plugin, you're not alone. This is a common issue affecting many users. This guide will explain why these warnings occur and what you can do about them.

Understanding the Problem

PHP 8.4 introduced a stricter requirement for function parameter declarations. Specifically, it now mandates that any parameter which can accept a null value must be explicitly marked as nullable using the question mark (?) syntax. The warnings you are seeing are not errors that break your site's functionality; they are deprecation notices pointing out code that will need to be updated for future PHP versions.

The most common warnings reported are:

  • Symfony Dependency Injection Container: Deprecated: YoastSEO_VendorSymfonyComponentDependencyInjectionContainer::__construct(): Implicitly marking parameter $parameterBag as nullable is deprecated...
  • League OAuth2 Client: Deprecated: YoastSEO_VendorLeagueOAuth2ClientProviderAbstractProvider::authorize(): Implicitly marking parameter $redirectHandler as nullable is deprecated...
  • GuzzleHTTP Client: Deprecated: YoastSEO_VendorGuzzleHttpClient::getConfig(): Implicitly marking parameter $option as nullable is deprecated...

These warnings originate from third-party libraries (Symfony, Guzzle, League) that are bundled and prefixed within the Yoast SEO plugin. The core issue is that the function signatures in these libraries need to be updated for PHP 8.4 compliance.

Common Solutions

1. Wait for an Official Plugin Update

The most straightforward solution is to wait for the Yoast SEO development team to release an update that includes versions of these third-party libraries with the corrected parameter declarations. This is the recommended and safest approach for most users, as manually editing plugin files is not advised and can lead to instability or cause your changes to be overwritten by the next update.

2. Disable Deprecation Notices on a Live Site

Since these are deprecation notices and not fatal errors, they do not affect your website's front-end functionality for visitors. If the notices are only visible in your logs or on a development site, you can safely suppress them on your live production environment.

To disable the display of errors and warnings, ensure your wp-config.php file has the following settings:

define( 'WP_DEBUG', false );
define( 'WP_DEBUG_DISPLAY', false );
define( 'WP_DEBUG_LOG', false );

This is a standard practice for live WordPress sites to ensure a smooth user experience.

3. A Note on Manual Code Edits (Advanced Users Only)

Some advanced users in the community have shared specific code edits to fix these warnings. For example, changing a function parameter from $parameterBag = null to ?$parameterBag = null. BugWP.com does not recommend manually editing plugin core files. These edits will be reverted the next time you update the plugin, potentially reintroducing the warnings and creating a maintenance burden. This information is provided for educational purposes only.

Conclusion

The PHP 8.4 deprecated warnings are a forward-looking compatibility notice. Your site should continue to operate normally. The optimal solution is to monitor the official plugin development channel for an update that addresses these PHP 8.4 compatibility issues. Until then, disabling debug output on your live site is a practical workaround.

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