Problem: The client was experiencing a critical error on their website, which could not load at all. The error was triggered on wp-login.php with a message: 'Uncaught TypeError: in_array(): Argument #2 ($haystack) must be of type array, null given in /wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Lst.php:203'. The client had questions regarding PHP 8.4.13 compatibility with WPML and the permanent fix for the error in Lst.php line 203. Solution: We recommended the following steps to resolve the issue: 1. Visit https://wpml.org/account/downloads/ 2. Download fresh copies of all WPML plugins. 3. Delete the existing WPML plugins from the site (note: this will not remove translations or settings). 4. Upload the newly downloaded versions. 5. Try activating them again. Additionally, we asked the client to confirm whether the installation was a standard WordPress setup or if there was a specific hosting environment or custom setup involved.
If this solution does not resolve your issue, or if it seems outdated or irrelevant to your case, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If further assistance is needed, please open a new support ticket at WPML support forum.
