TL;DR

Redux now correctly handles objects created with Object.create(null) (empty objects) and ensures the store state type is nullable, improving compatibility and type safety.

Fixes Worth Knowing

Redux now correctly identifies objects created without a prototype as plain objects. This resolves issues when using Redux with data structures that don’t inherit from Object.prototype (common JavaScript pattern).

Before You Upgrade

No action is needed; this is a patch release addressing compatibility and type definitions.

TL;DR

Redux 5.0 is coming soon, alongside Redux Toolkit 2.0, and introduces new TypeScript utilities for safer action handling.

Breaking

• TypeScript Middleware Types: Middleware now receives actions as type unknown, requiring explicit type guards (type checking) for correct usage. (See migration guide)

New

• isAction Predicate: A new function to reliably determine if a value is a Redux action.
• isPlainObject Utility: An internal utility function is now exported for checking object types.

Fixes Worth Knowing

None.

Before You Upgrade

Review the Redux Toolkit 2.0 + Redux core 5.0 Migration Guide to prepare for potential breaking changes in related packages.

TL;DR

Redux now fully supports modern JavaScript bundlers (tools for packaging code) without requiring specific production build settings, resolving compatibility issues with platforms like Expo.

Breaking

• Removed internal minification check – may affect custom builds relying on this behavior (unlikely).

Fixes Worth Knowing

• Resolved compatibility issues with Expo and similar bundlers.

Before You Upgrade

No action is needed; this is a bugfix release.

TL;DR

Redux 4.1 reduces bundle size by replacing verbose error messages with concise error codes (unique identifiers) in production builds.

Breaking

• Error messages are now codes (for smaller bundles).

New

• TypeScript definitions are improved (for better type safety).

Fixes Worth Knowing

• Runtime type check errors now include more helpful details and documentation links.

Before You Upgrade

If you rely on parsing Redux error messages, update your code to handle error codes instead.

TL;DR

Redux now fully supports TypeScript 2.4, resolving type definition issues for users of that TypeScript version.

Breaking

• Reducer type definitions changed (for TypeScript 2.4 users).

Fixes Worth Knowing

• TypeScript 2.4 compatibility improved (popular JavaScript/TypeScript tool).

Before You Upgrade

If you are using TypeScript 2.4 with Redux, ensure your reducer types are updated to reflect the new definitions.

TL;DR

Redux v2.0.0 introduces breaking changes to how compose() and reducer hot reloading work, requiring updates to store configuration and potentially Webpack setup.

Breaking

• getReducer() removed: If you used reducer hot reloading, update your store creation to use module.hot.accept() and store.replaceReducer(). (Webpack configuration)
• compose() behavior changed: Adjust how you apply middleware and store enhancers; apply createStore as a function to the composed function. (Function application)
• process.env.NODE_ENV required: Ensure process.env.NODE_ENV is defined in your CommonJS environment. (Environment variable)

Before You Upgrade

• If using reducer hot reloading, implement the module.hot.accept() pattern shown in the release notes.
• Verify process.env.NODE_ENV is set in your build environment if using CommonJS.

TL;DR

Redux 1.0 is released with significant documentation and examples, but introduces a breaking change: reducers can no longer dispatch actions during execution.

Breaking

• Reducers cannot dispatch actions during execution. (Prevents unexpected behavior and infinite loops.)

New

• Comprehensive documentation is now available. (Gitbook platform)
• New examples demonstrate async applications and real-world patterns. (Includes caching, normalization, and middleware.)

Fixes Worth Knowing

• Fixed “process is not defined” error in React Native. (Improves mobile development experience.)
• Resolved issues with unsubscribing during dispatch. (Enhances component update reliability.)

Before You Upgrade

• If migrating from Redux 0.12, first apply the 0.12 -> 1.0.0-alpha and then 1.0.0-alpha -> 1.0.0-rc migrations before upgrading to 1.0.

TL;DR

Redux has undergone a major refactoring, moving React bindings to a separate react-redux package and introducing breaking changes to store creation and middleware application, requiring updates to how state is managed and actions are dispatched.

Breaking

• React Bindings Moved: React-specific code is now in react-redux. Update imports from redux/react to react-redux.
• createStore Changes: createStore no longer implicitly combines reducers or accepts middleware directly. Use combineReducers and applyMiddleware explicitly.
• Middleware Signature: All middleware now requires a { getState, dispatch } parameter.
• Thunk Middleware: redux-thunk is no longer included by default and must be installed and applied separately.
• Reducer Initial State: Reducers must now return a default state or handle undefined state, as returning undefined will now throw an error.
• @@INIT Action: The @@INIT action is deprecated; reducers should handle initial state based on undefined state input.

New

None

Fixes Worth Knowing

• Components now update

TL;DR

Redux now supports React Native and introduces middleware (function-based action dispatch) for managing asynchronous logic, replacing the previous function-returning action creator approach.

Breaking

• React Native Support: Imports for React-specific components must now come from redux/react or redux/react-native.
• Asynchronous Actions: Function-returning action creators are deprecated; use thunkMiddleware instead.

New

• Middleware: Enables asynchronous actions and side effects within Redux.
• React Native: Adds support for building React Native applications with Redux.

Fixes Worth Knowing

• Connector now correctly recalculates state when select changes.
• getState now returns the current state after hot reloading.
• Connector validates that select returns a plain object.

Before You Upgrade

• Update your imports to use redux/react or redux/react-native when working with React Native.
• Migrate any function-returning action creators to use thunkMiddleware.