---
title: Agent - 4.3.0
slug: feature-experimentation/release-notes/agent-4-3-0
docTags: 
createdAt: 2026-07-20T15:45:20.513Z
---

## \[4.3.0] - November 20, 2025

[#430---november-20-2025](docId:7c4ys_ARCpBGUSQumkqjk)

## Contextual Multi-Armed Bandit (CMAB) Support

[#contextual-multi-armed-bandit-cmab-support](docId:7c4ys_ARCpBGUSQumkqjk)

This release introduces production-ready support for **Contextual Multi-Armed Bandit (CMAB)**, enabling AI-powered experimentation that learns and adapts in real-time based on user context.

### Key Features

[#key-features](docId:7c4ys_ARCpBGUSQumkqjk)

**CMAB Support** - First stable Agent release with full CMAB capabilities:

- Full CMAB decision API integration using go-sdk v2.1.1
- In-memory LRU cache (default: 10,000 entries, 30m TTL)
- Redis cache for multi-instance deployments with shared decision caching
- Configurable prediction endpoint for testing/staging environments
- Flexible Redis authentication (auth\_token, redis\_secret, password fields)

**Redis Streams with Auto-Detection** - Intelligent notification sync:

- Automatic Redis version detection at startup
- Redis >= 5.0: Uses Redis Streams (persistent, acknowledged delivery with batching)
- Redis \< 5.0: Falls back to Redis Pub/Sub
- Configurable batching, flush intervals, and retry logic

**Enhanced Redis Authentication** - Security scanner friendly:

- Supports multiple auth field names across all Redis services (ODP, UPS, CMAB, synchronization)
- Environment variable fallbacks: REDIS\_PASSWORD, REDIS\_ODP\_PASSWORD, REDIS\_UPS\_PASSWORD, REDIS\_CMAB\_PASSWORD, REDIS\_PUBSUB\_PASSWORD

### Related Pull Requests

[#related-pull-requests](docId:7c4ys_ARCpBGUSQumkqjk)

- [#446](https://github.com/optimizely/agent/pull/446) - CMAB Config API Update
- [#447](https://github.com/optimizely/agent/pull/447) - CMAB Redis Cache Support
- [#448](https://github.com/optimizely/agent/pull/448) - Redis Streams Integration with Auto-Detection

**Full Changelog**: [https://github.com/optimizely/agent/compare/v4.2.2...v4.3.0](https://github.com/optimizely/agent/compare/v4.2.2...v4.3.0)

[https://github.com/optimizely/agent/releases/tag/v4.3.0](https://github.com/optimizely/agent/releases/tag/v4.3.0)