---
title: Agent - 4.2.1
slug: feature-experimentation/release-notes/agent-4-2-1
docTags: 
createdAt: 2026-07-20T15:45:18.343Z
---

## \[4.2.1] - September 3, 2025

[#421---september-3-2025](docId\:s9yhRWjyIlYaNW2AJYH3k)

### Fixed

[#fixed](docId\:s9yhRWjyIlYaNW2AJYH3k)

- Fixed decision notifications not working with secure environment SDK keys
- Added documentation for Redis channel naming pattern in config.yaml
- [PR 441](https://github.com/optimizely/agent/pull/441)

***

## Additional Technical Details

[#additional-technical-details](docId\:s9yhRWjyIlYaNW2AJYH3k)

### Features

[#features](docId\:s9yhRWjyIlYaNW2AJYH3k)

- **Secure token parsing**: Handle SDK keys with secure tokens in format `sdkKey:apiKey` for notification endpoints
- Enhanced notification handler to extract SDK key from secure token format

### Bug Fixes

[#bug-fixes](docId\:s9yhRWjyIlYaNW2AJYH3k)

- Fixed notification handler test hanging issues
- Updated Go version to 1.23 for better compatibility
- Updated Alpine Docker base image from 3.21 to 3.20 for Go 1.23 compatibility
- Fixed test timeouts and formatting

### Documentation

[#documentation](docId\:s9yhRWjyIlYaNW2AJYH3k)

- Improved Redis subscription documentation in config.yaml
- Added comprehensive unit tests for secure token parsing (7 test cases)

**Full Changelog**: [https://github.com/optimizely/agent/compare/v4.2.0...v4.2.1](https://github.com/optimizely/agent/compare/v4.2.0...v4.2.1)

[https://github.com/optimizely/agent/releases/tag/v4.2.1](https://github.com/optimizely/agent/releases/tag/v4.2.1)