WordPress Delays React 19 Upgrade Due to Plugin Compatibility Issues

WordPress has postponed the integration of React 19 into its 7.1 release due to significant plugin compatibility concerns. The decision means the platform will continue to utilize React 18.3 for the foreseeable future.

The WordPress development team detected potential issues during internal testing of React 19 within the Gutenberg plugin. These problems stemmed from how some third-party plugins handle React's JSX runtime. Instead of using WordPress's standardized shared script for react-jsx-runtime, certain developers bundle their own React code directly into their plugins.

This practice leads to conflicts where plugins might simultaneously run code for both React 18 and React 19. When older data structures created with React 18 are processed by React 19's runtime, incompatibilities can emerge. Such issues could manifest as broken block functionalities, errors in the backend interface, or JavaScript errors in browser developer consoles.

To address this, WordPress is developing an automated detection tool within its Plugin Check feature. This tool will identify plugins that either bundle their own JSX runtime or rely on deprecated React features removed in version 19. The development team urges plugin authors to test their code thoroughly and report any compatibility problems to the Gutenberg project's GitHub repository.

Further complicating the transition, many existing plugins still depend on features that are either deprecated or have been removed in React 19. While the WordPress team is implementing backward compatibility layers for some of these functions, they acknowledge that this support is currently insufficient to guarantee a smooth transition for all plugins.