---
title: Javascript-SDK - 1.5.1
slug: feature-experimentation/release-notes/javascript-sdk-1-5-1
docTags: 
createdAt: 2026-07-20T15:45:18.937Z
---

\* Bump optimizely-server-sdk to version 1.4.2, which includes:
\- Bug fix to filter out undefined values in attributes and event tags
\- Remove a duplicated test

[https://github.com/optimizely/javascript-sdk/releases/tag/v1.5.1](https://github.com/optimizely/javascript-sdk/releases/tag/v1.5.1)