WordPress 5.5 was released last night, and it began the long process of updating the bundled jQuery javascript library to a more current version. Unfortunately, it also broke a number of plugins and themes, causing javascript errors and strange behavior throughout the dashboard and front end.

The first problem I noticed on my site were broken hover states in the WordPress admin dashboard. Typically, when you hover the Posts or Pages or any side menu in the dashboard, a submenu appears to display the related options.

The cause turned out to be the removal of a script called jQuery migrate from the WordPress core — a necessary first step in the jQuery update process. The solution is to put the script back. Fortunately, the WP core team anticipated this would be an issue on some sites and kindly provided a free plugin to address the issue.

If you notice strange behavior after updating — and especially if you see errors in the javascript console — try installing the Enable jQuery Migrate Helper plugin. It fixed my issues straight away.

Are you struggling with updates or other problems on your WordPress site? Book an appointment in my WP Clinic, and we’ll work through it together.