WordPress 6.4 Rollout Leads to Breakages with Leading Page Builder Plugin

WordPress 6.4 Rollout Leads to Breakages with Leading Page Builder Plugin

Many website owners encountered unforeseen issues when WordPress 6.4, also known as pseudonym "Shirley," was released. Soon after the update, many publishers and developers reported that their websites crashed and displayed fatal errors.

Users soon discovered a common denominator after investigating the problem: the Oxygen page builder plugin was installed on all affected websites.

Initial Reports Surface

Within hours of the 6.4 release, the first alerts emerged. The update was shortly followed by members of private WordPress groups reporting experiences of unexpected crashes. As discussions progressed, it became evident that not all WordPress installations were experiencing the problem. Rather, it seemed to be restricted to locations where Oxygen was installed. Developers quickly found another similarity amongst the impacted websites, though.

Legacy Default Themes Linked to The Problem

Brenda Malone, a WordPress developer and SEO specialist, noted that outdated default WordPress themes were also installed on sites that had issues. Twenty Twenty-One and Twenty Twenty-Two are two examples of these default themes. The existence of such legacy themes in the themes folder appeared to cause issues when Oxygen was installed, even if they were deactivated. The fatal problem seemed to be caused by just leaving the server's default themes outdated.

One user reported that deleting the older themes immediately restored their site functionality.

Temporary Fixes Shared by The Community

In user groups dedicated to Oxygen, members proposed a workaround:

Activate WordPress recovery mode, remove all outdated default themes, and install the newest default theme, Twenty Twenty-Four. For many site owners, this solution resolved the issue without needing further troubleshooting.

What Caused the Crash?

One theory shared in the Oxygen community suggested that an active theme might have been loading its default CSS styles in a way that conflicted with Oxygen’s framework. In at least one case, removing CSS from the Oxygen “bare minimum” theme eliminated the crash. While the exact technical trigger wasn’t immediately confirmed, the Oxygen development team acknowledged the issue and began working on a fix.

Official Patch Released

Shortly afterward, the Oxygen team released version 4.7.1, specifically addressing compatibility issues with WordPress 6.4. They advised users to update Oxygen first before upgrading their WordPress installation to avoid further problems.

Final Thoughts

Software updates often improve performance and security, but they can also expose compatibility gaps between core platforms and third-party plugins. In this case, the issue appeared limited to a specific combination of WordPress 6.4, Oxygen, and legacy default themes