# MobX 7.0.0

- Product: MobX (https://whatsnew.fyi/product/mobx)
- Vendor: MobX
- Date: 2026-07-30
- Version: 7.0.0
- Original notes: https://github.com/mobxjs/mobx/releases/tag/mobx%407.0.0
- Permalink: https://whatsnew.fyi/product/mobx/releases/7.0.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **removed** — ES5/non-proxy fallback for observable objects and arrays; MobX now always uses Proxy-backed observables
- **removed** — configure({ useProxies: ... }) option
- **removed** — { proxy: false } option for observable, observable.object, and observable.array
- **removed** — Legacy decorators support
- **removed** — Namespaced annotation properties observable.ref, observable.shallow, observable.deep, and observable.struct in favor of named exports observableRef, observableShallow, observableDeep, and observableStruct
- **removed** — Namespaced comparer and computed properties comparer.identity, comparer.default, comparer.structural, comparer.shallow, computed.struct, action.bound, and flow.bound in favor of named exports compareIdentity, compareDefault, compareStructural, compareShallow, computedStruct, actionBound, and flowBound
- **removed** — Public trace API and related runtime support; use toJS, getDependencyTree, getObserverTree, spy or mobx-log package for debugging
- **changed** — mobx-react-lite now requires MobX 7 and React 18 or later
- **changed** — mobx-react now requires MobX 7 and React 18 or later
- **removed** — Provider, inject, and MobXProviderContext from React binding packages; use React.createContext directly
- **removed** — disposeOnUnmount from React binding packages; dispose reactions in componentWillUnmount or return cleanup functions from useEffect
- **removed** — PropTypes export from React binding packages; use TypeScript or the regular prop-types package
- **removed** — useObserver from React binding packages; wrap components with observer or use <Observer>
- **removed** — useLocalStore from React binding packages; use useLocalObservable instead
- **removed** — useAsObservableSource from React binding packages; synchronize values from props into local observable state explicitly
- **removed** — useStaticRendering from React binding packages; use enableStaticRendering instead
- **removed** — observerBatching, isObserverBatched, batchingForReactDom, batchingOptOut, and batchingForReactNative from React binding packages; React 18+ renderers handle batching
- **deprecated** — observer(fn, { forwardRef: true }) syntax; pass an already-created React.forwardRef(...) component to observer instead
- **removed** — Legacy function-component contextTypes handling from React binding packages
- **changed** — Minified error URLs shortened to reduce production bundle size

###### Major Changes

-   [`1926c69f53168619d688f348aa587e8f3ae579ae`](https://github.com/mobxjs/mobx/commit/1926c69f53168619d688f348aa587e8f3ae579ae) [#4671](https://github.com/mobxjs/mobx/pull/4671) Thanks [@kubk](https://github.com/kubk)! - Release MobX 7, mobx-react-lite 5, and mobx-react 10.

    Bundle sizes are down: ESM prod 17.02 KiB gzip -> 13.96 KiB gzip; a minimal tree-shaken example is 10.32 KiB gzip now.

    It removes long-deprecated compatibility paths and keeps the React bindings split between `mobx-react-lite` for function components and `mobx-react` for class-component support.

    ## MobX 7

    MobX 7 is a cleanup release focused on the modern runtime and decorator model.

    -   MobX now always uses Proxy-backed observable objects and arrays. The ES5/non-proxy fallback has been removed.
    -   `configure({ useProxies: ... })` is no longer supported.
    -   `{ proxy: false }` options for `observable`, `observable.object`, and `observable.array` are no longer supported.
    -   Legacy decorators are no longer supported.
    -   Namespaced annotation and comparer properties now use named exports to reduce bundle size:

    | Removed API           | Replacement         |
    | --------------------- | ------------------- |
    | `observable.ref`      | `observableRef`     |
    | `observable.shallow`  | `observableShallow` |
    | `observable.deep`     | `observableDeep`    |
    | `observable.struct`   | `observableStruct`  |
    | `computed.struct`     | `computedStruct`    |
    | `action.bound`        | `actionBound`       |
    | `flow.bound`          | `flowBound`         |
    | `comparer.identity`   | `compareIdentity`   |
    | `comparer.default`    | `compareDefault`    |
    | `comparer.structural` | `compareStructural` |
    | `comparer.shallow`    | `compareShallow`    |

    -   The public `trace` API and its related runtime support have been removed. Use `toJS`, `getDependencyTree`, `getObserverTree`, `spy` or `mobx-log` package for debugging.

    ## mobx-react-lite 5 and mobx-react 10

    mobx-react-lite 5 and mobx-react 10 require MobX 7 and React 18 or later.

    `mobx-react-lite` remains the function-component package. `mobx-react` remains a thin wrapper around `mobx-react-lite` that adds class component and Stage 3 `@observer` class decorator support.

    -   Keep function-component imports on `mobx-react-lite` if you do not need class component support.
    -   Use `mobx-react` when you need class components or `@observer` class decorators.
    -   `mobx-react-lite` supports function components and `forwardRef`; `mobx-react` delegates function components to `mobx-react-lite` and handles classes itself.
    -   Remove React batching imports, including the stale React Native batching deep import. React 18+ renderers handle batching.

    The recommended public React binding surface for both packages is:

    -   `observer`
    -   `Observer`
    -   `useLocalObservable`
    -   `enableStaticRendering`
    -   `isUsingStaticRendering`

    The following APIs have been removed from the React binding packages:

    -   `Provider`, `inject`, and `MobXProviderContext`; use `React.createContext` directly.
    -   `disposeOnUnmount`; dispose reactions in `componentWillUnmount` or return cleanup functions from `useEffect`.
    -   `PropTypes`; use TypeScript or the regular `prop-types` package.
    -   `useObserver`; wrap components with `observer` or use `<Observer>`.
    -   `useLocalStore`; use `useLocalObservable`.
    -   `useAsObservableSource`; synchronize values from props into local observable state explicitly.
    -   `useStaticRendering`; use `enableStaticRendering`.
    -   `observerBatching`, `isObserverBatched`, `batchingForReactDom`, `batchingOptOut`, and `batchingForReactNative`; remove these imports because React 18+ renderers handle batching.
    -   Deprecated `observer(fn, { forwardRef: true })`; pass an already-created `React.forwardRef(...)` component to `observer` ins

_[Truncated at 4000 characters — full notes: https://github.com/mobxjs/mobx/releases/tag/mobx%407.0.0]_