This release is identical to 18.2 but adds warnings for deprecated APIs and other changes that are needed for React 19.

Read the React 19 Upgrade Guide for more info.

React

• Allow writing to this.refs to support string ref codemod 909071
• Warn for deprecated findDOMNode outside StrictMode c3b283
• Warn for deprecated test-utils methods d4ea75
• Warn for deprecated Legacy Context outside StrictMode 415ee0
• Warn for deprecated string refs outside StrictMode #25383
• Warn for deprecated defaultProps for function components #25699
• Warn when spreading key #25697
• Warn when using act from test-utils d4ea75

React DOM

• Warn for deprecated unmountComponentAtNode 8a015b
• Warn for deprecated renderToStaticNodeStream #28874