---
title: Javascript-SDK - 4.0.0-alpha.1
slug: feature-experimentation/release-notes/javascript-sdk-4-0-0-alpha-1
docTags: 
createdAt: 2026-07-20T15:44:23.109Z
---

\## \[4.0.0-alpha.1] - April 2, 2020

\### Breaking Changes:
\- Removed \`Promise\` polyfill from browser entry point (\[417]\([https://github.com/optimizely/javascript-sdk/pull/417](https://github.com/optimizely/javascript-sdk/pull/417)))

[https://github.com/optimizely/javascript-sdk/releases/tag/v4.0.0-alpha.1](https://github.com/optimizely/javascript-sdk/releases/tag/v4.0.0-alpha.1)