Thousands of WordPress sites have become broken since updating to WordPress 5.5. One of the reasons is because WP 5.5 deprecated support for jQuery Migrate, which may have caused at least 10,000 broken sites. An issue with how themes handle pagination is causing other sites to break after updating to 5.5.

Fortunately there are solutions.

A publisher reported a bug in WordPress 5.5

jQuery Migrate and WordPress 5.5

Thousands of WordPress publishers are experiencing problems because WordPress 5.5 shipped without a JavaScript library called jQuery Migrate.

jQuery Migrate is a library that acts like a bridge for older code to function on WordPress.

However when publishers stick to an older theme, particularly one that is no longer being updated, compatibility issues eventually creep in and that’s what happened with WordPress 5.5.

What Kind of Errors Are Sites Experiencing?

JavaScript can be thought of like little machines that make things happen.

The scripts work behind the scenes to make forms, search bars, and drop down menus work.

What is Causing JavaScript Errors in WordPress 5.5?

The cause of some of the issues are older plugins. For others, the cause of the problem are older WordPress themes.

The publisher in the screenshot above reported a critical bug to WordPress that prevented them from publishing articles and featured images:

The publisher reported:

“Your last update is a pure disaster. I used the classic editor plugin because your block editor is a full mess, and now it does not work anymore since your update. I can only edit in HTML mode and not in visual!

So I tried to publish my last article in your block editor, but impossible to add a featured image, I have a white page with “Featured image” title showing on the top and that is all.”

The source of the problem was an older plugin that relied on jQuery Migrate Library to function. The plugin stopped working after WordPress removed that library.

The problem wasn’t really the fault of WordPress. The problem was caused by an older and outdated plugin.

The Stack Overflow forum is also experiencing questions related to WordPress 5.5. and sites losing functionality.

This person asked for help regarding a problem that was caused by an outdated theme that is experiencing loss of dropdown menu and slider functionality.

Screenshot of a question on stack overflow about an older theme not working after updating to WordPress 5.5.

What caused the problem was older JavaScript in an outdated WordPress theme.

The solution to this problem is easy.

How to Fix jQuery Migrate Bug

If the issue is related to a plugin that is using older JavaScript files, check out when was the last time that plugin was updated. If the last time it was updated was a year or longer, you might want to consider looking for another plugin that is more up to date.

Older plugins that are abandoned can become a security risk. Better to update to a new and well maintained plugin than continue using a plugin that might have security issues.

WordPress has released a plugin that restores the jQuery Migrate JavaScript library and restores the full function of a website.

If you’re experiencing a lack of functionality and your Chrome developer console is showing JavaScript errors, plus your theme or a plugin is older, then installing this plugin may help you.

The name of the plugin is called, Enable jQuery Migrate Helper.

The WordPress Enable jQuery Migrate plugin has been downloaded over 10,000 times in the few days since it’s been released.

That’s a lot of publishers who were affected by this issue and there are likely going to be more who are seeking this solution.

WordPress 5.5 Pagination Bug

Updating to WordPress is causing pagination to fail on some sites.

Pagination is a reference to the navigational page numbers at the bottom of a multi-page document, usually in a category section of a website.

Pagination is part of the navigational structure of a website. It allows site visitors to find web pages deep in a site.

An official bug report was filed about this issue at WordPress

According to a publisher:

“After upgrading to 5.5 the page parameter is being dropped from the URL with 301 redirect… This was breaking our site…. I would like to install 5.5 but this is breaking the site.”

Others reported that this is affecting many of their clients

“This is pretty major due to the fact that many themes/plugins are using this query param. Clients are going nuts as we speak.”

What is happening is that there is a conflict in the use of the word “page.” WordPress uses it for pagination but only with a numerical value.

Themes are using the word “page” with additional non-numerical values.

According to WordPress Core Contributor  Sergey Biryukov (@SergeyBiryukov):

“It should only have a numeric value, and is not meant to be used for any other purpose, e.g. ?page=offers&id=xxx.

So I would recommend changing this variable in any custom code to some other name to avoid conflicts.

As another possible solution, you can disable the redirect_canonical() function for these requests, that is attached to the template_redirect action by default.”

A publisher posted a workaround:

“Have downgraded for now which works and will rebuild the theme using ‘mypage=’ instead of ‘page=’ in the query string.”

WordPress 5.5 Largely a Success

For the most part, WordPress 5.5 is a success. I spent a few hours reviewing the list of possible bugs and was impressed by the work the WordPress community was doing to research each problem to figure them all out.

The WordPress team is doing an amazing job.

There are some issues related to WordPress 5.5 that have possibly affected thousands of publishers. But those problems are fairly easy to fix once the cause is identified.