WordPress 5.7 Ushers Out Legacy jQuery
WordPress core is completing its transition to modern jQuery with the upcoming 5.7 release, scheduled for March 9. The move brings the bundled library from jQuery 1.12.4 up to jQuery 3.5.1, a long-anticipated shift driven by the need for current features, better developer experience, and improved security.
This marks the final phase of a deliberate, three-step process that began in WordPress 5.5. The groundwork continued in 5.6, where core made the initial jump to jQuery 3.5.1 while still shipping jQuery Migrate—a compatibility layer that lets developers temporarily fall back to legacy behavior. With 5.7, that migration helper is scheduled to be disabled, cutting off the safety net for good.
What Changes for Developers
The significance here is that WordPress ships its own copy of jQuery, and many themes and plugins rely on that bundled version rather than enqueuing their own. Because of WordPress’s strong commitment to backward compatibility, breaking changes of this scale are rare. That makes this transition notable: any code written against the older API may now fail if it hasn’t been updated to be compatible with jQuery 3.x.
Developers who haven't yet verified their code against jQuery 3.x should treat the 5.6 release as their testing window. Fixing issues after upgrading to 5.7 will be considerably harder, since the Migrate plugin—and the automatic rollback features it provides—will be gone.
Tools for a Smooth Transition
The WordPress team has published an official plugin, Enable jQuery Migrate Helper, designed to ease this exact scenario. The helper can automatically revert a site to jQuery 1.x when it detects a compatibility failure, record those errors for the site administrator, and send notifications when problems occur. It’s a practical safeguard for site owners who aren’t sure whether their third-party code is ready.
WordPress also maintains detailed troubleshooting documentation, and community guides cover step-by-step preparation strategies. The core team’s structured rollout—spanning multiple releases with ample communication—has given the ecosystem a rare opportunity to prepare well in advance of a breaking change.
