PHP 8.5 compatibility - Deprecated: Using null as an array offset is deprecated for /wp-login.php page

[ilicfilip]

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• I've searched for any related issues and avoided creating a duplicate issue.

Please give us a description of what happened

After updating to WordPress 6.9 and bumping PHP version to 8.5 I am getting PHP notices in the PHP error log.

To Reproduce

Visiting the /wp-login.php page will trigger following:

Deprecated: Using null as an array offset is deprecated, use an empty string instead in /****/htdocs/wp-content/plugins/wordpress-seo/src/memoizers/meta-tags-context-memoizer.php on line 135
Deprecated: Using null as an array offset is deprecated, use an empty string instead in /****/htdocs/wp-content/plugins/wordpress-seo/src/memoizers/presentation-memoizer.php on line 49
Deprecated: Using null as an array offset is deprecated, use an empty string instead in /****/htdocs/wp-content/plugins/wordpress-seo/src/memoizers/presentation-memoizer.php on line 63
Deprecated: Using null as an array offset is deprecated, use an empty string instead in /****/htdocs/wp-content/plugins/wordpress-seo/src/memoizers/presentation-memoizer.php on line 66
Deprecated: Using null as an array offset is deprecated, use an empty string instead in /****/htdocs/wp-content/plugins/wordpress-seo/src/memoizers/meta-tags-context-memoizer.php on line 154
Deprecated: Using null as an array offset is deprecated, use an empty string instead in /****/htdocs/wp-content/plugins/wordpress-seo/src/memoizers/meta-tags-context-memoizer.php on line 157

Intermittently, in WP Dashboard, I get following as well:

[10-Dec-2025 08:55:01 UTC] PHP Deprecated:  YoastSEO_Vendor\League\OAuth2\Client\Provider\AbstractProvider::authorize(): Implicitly marking parameter $redirectHandler as nullable is deprecated, the explicit nullable type must be used instead in /****/htdocs/wp-content/plugins/wordpress-seo/vendor_prefixed/league/oauth2-client/src/Provider/AbstractProvider.php on line 416
[10-Dec-2025 08:55:01 UTC] PHP Deprecated:  YoastSEO_Vendor\GuzzleHttp\Client::getConfig(): Implicitly marking parameter $option as nullable is deprecated, the explicit nullable type must be used instead in /****/htdocs/wp-content/plugins/wordpress-seo/vendor_prefixed/guzzlehttp/guzzle/src/Client.php on line 181
[10-Dec-2025 08:55:01 UTC] PHP Deprecated:  YoastSEO_Vendor\GuzzleHttp\ClientInterface::getConfig(): Implicitly marking parameter $option as nullable is deprecated, the explicit nullable type must be used instead in /****/htdocs/wp-content/plugins/wordpress-seo/vendor_prefixed/guzzlehttp/guzzle/src/ClientInterface.php on line 77

Used versions

• Device you are using: MacBook
• Operating system: MacOS, Valet
• PHP version: 8.5
• WordPress version: 6.9
• WordPress Theme: 2025
• Yoast SEO version: 26.5

[josevarghese]

Hi @ilicfilip

Thanks for creating the issue. The PHP deprecation message for OAuth2 and GuzzleHttp will be fixed in Yoast SEO 26.6. You can find the PR here.

Regarding the 'Deprecated' message displayed on the /wp-login.php page, I can replicate it on the PHP 8.5 version and inform the development team. The development team also confirmed that it should not be shown on that page, as we exclude those kinds of pages.

What's next?
Our product team will assess the severity of this problem in relation to other open reports and new features. Based on their assessment, the report will be given a priority level. Our developers work on the highest priority issues first. Unfortunately, this means we cannot give you an estimate of when they'll start working on your report.

[josevarghese]

Internal Slack conversation: https://yoast.slack.com/archives/C01NCRHHN30/p1765365606645929