Fixing WPML Plugin Error After Updating to WordPress 6.1
❗ The Problem
After updating to WordPress 6.1, your site throws a fatal error:
Fatal error: Uncaught Error: Call to undefined method WP_Textdomain_Registry::reset()
in LanguageSwitch.php on line 139
This happens only on sites using WPML, and deactivating the WPML plugins brings the site back—though that’s only a temporary solution.
✅ The Cause
WordPress 6.1 introduced breaking changes that require updated versions of WPML and its add-ons. Older versions are incompatible and throw errors, as seen above.
WPML’s Statement:
WPML Multilingual CMS 4.5.12 and WPML String Translation 3.2.3 are required for compatibility with WordPress 6.1.
View official changelog →
🛠️ Permanent Fix: Update WPML Plugins
Follow these steps:
Backup your website (just to be safe).
Download the latest WPML plugins from your account:
https://wpml.org/account/downloads/Manually update via FTP or File Manager:
Deactivate current WPML plugins.
Delete the plugin files (not the database).
Upload the latest plugin versions.
Reactivate them.
📄 Full instructions: Updating WPML Manually
You won’t lose any translation data—WPML stores them in the database.
🩹 Quick Fix: Temporary Workaround (Not Recommended Long-Term)
If you can’t update WPML right away, use this quick patch:
Go to:
/wp-content/plugins/wpml-string-translation/classes/MO/Hooks/LanguageSwitch.php
On line 139, change this:
$wp_textdomain_registry->reset();
To:
reset($wp_textdomain_registry);
💡 This bypasses the missing method error—but it’s not future-proof. Always plan to upgrade.
✅ Final Thoughts
WordPress core updates can introduce breaking changes—especially when working with plugins as deep as WPML. Staying on top of plugin versions ensures smooth performance and fewer surprises.