---
title: Javascript-SDK - 4.2.0
slug: feature-experimentation/release-notes/javascript-sdk-4-2-0
docTags: 
createdAt: 2026-07-20T15:44:20.696Z
---

\## \[4.2.0] - July 31, 2020

\### New Features
\- Better offline support in React Native apps:
\- Persist downloaded datafiles in local storage for use in subsequent SDK initializations (\[#430]\([https://github.com/optimizely/javascript-sdk/pull/430](https://github.com/optimizely/javascript-sdk/pull/430)))
\- Persist pending impression & conversion events in local storage (\[#517]\([https://github.com/optimizely/javascript-sdk/pull/517](https://github.com/optimizely/javascript-sdk/pull/517)), \[#532]\([https://github.com/optimizely/javascript-sdk/pull/532](https://github.com/optimizely/javascript-sdk/pull/532)))

\### Bug fixes
\- Fixed log messages for Targeted Rollouts (\[#515]\([https://github.com/optimizely/javascript-sdk/pull/515](https://github.com/optimizely/javascript-sdk/pull/515)))

[https://github.com/optimizely/javascript-sdk/releases/tag/v4.2.0](https://github.com/optimizely/javascript-sdk/releases/tag/v4.2.0)