# MobX 6.3.8

- Product: MobX (https://whatsnew.fyi/product/mobx)
- Vendor: MobX
- Date: 2021-11-27
- Version: 6.3.8
- Original notes: https://github.com/mobxjs/mobx/releases/tag/mobx%406.3.8
- Permalink: https://whatsnew.fyi/product/mobx/releases/6.3.8

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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- **changed** — Make IAtom['reportObserved'] return boolean
- **fixed** — Fix RangeError in ObservableArray.replace for large arrays

###### Patch Changes

-   [`9d5e65cb`](https://github.com/mobxjs/mobx/commit/9d5e65cbd612f262d925e57cebb559f5cf36c502) [#3193](https://github.com/mobxjs/mobx/pull/3193) Thanks [@ChocolateLoverRaj](https://github.com/ChocolateLoverRaj)! - Make `IAtom['reportObserved']` return `boolean`


-   [`55508af6`](https://github.com/mobxjs/mobx/commit/55508af690fa875e6affaf30f34280b3f27b6126) [#3189](https://github.com/mobxjs/mobx/pull/3189) Thanks [@RvanderLaan](https://github.com/RvanderLaan)! - Fix for RangeError in ObservableArray.replace for large arrays