WordPress 5.5 was released this week (August 2020), bringing us a number of new and improved features including UI improvements in Block Editor, a new Block Directory, Block Patterns and default lazy load images.
Despite the recommendation for developers to get ready for this update, it still caught many developers by surprise.
And because of that updating to WordPress 5.5 has broken quite a lot of sites. If your site is one of them, don’t panic. In this post, I’ll explain why WordPress 5.5 is breaking websites and how to fix it.
What changed that made my site break?
WordPress 5.5 discontinued support for jQuery Migrate, which is a Javascript library that was included to help plugins and themes run properly.
Update – WordPress 5.6 was released on December 8, 2020. This brings us to phase two of updating the outdated jQuery JavaScript library. This means some themes and plugins might not be compatible with WordPress 5.6, and may stop working.
While it is a pain and an inconvenience, there is a reason. The jQuery Migrate library has been deprecated for quite some time, so getting rid of its usage in WordPress Core is a rather important step in order to move WordPress forward and use the latest version of jQuery.
By removing this support, outdated plugins or themes will no longer function properly. But there is a fix!
Update: WordPress 5.5.1 maintenance release is supposed to fix this issue temporarily to allow developers more time to update their themes and plugins.
How do I fix it?
You can install and activate the jQuery Migrate Helper plugin to re-enable the removed support and temporarily fix the issue on your site.
This will also show you what theme or plugin is causing the issue so you can reach out to the developer for a long-term solution. And it will output error messages in your browser console.
You’ll also want to update all your themes and plugins to the latest versions. If you have a premium plugin or theme, you may need to renew your license key in order to update them to the latest version.
If there’s no update available, you may need to contact the developer to see if the theme or plugin is still being supported. You can find information on when they last update was on the right hand side of the plugin page too.
If a theme or plugin hasn’t been updated in a while, I’d recommend removing it as it may not work correctly anymore. Outdated themes and plugins also cause security issues.
Developers can also use the Test jQuery Updates plugin by the WordPress team to for check the different versions of jQuery for future compatibility.
Conclusion
As mentioned, these are temporary solutions. Going forward you’ll want to ensure that your theme and plugins all updates to support newer jQuery versions. If you need any WordPress help, I offer a Consult + Code service which includes site tweaks, customisations, code fixes, functionality updates and more.