---
title: Optimizely-Flutter-SDK - v3.4.0
slug: feature-experimentation/release-notes/optimizely-flutter-sdk-v3-4-0
docTags: 
createdAt: 2026-07-20T15:44:22.808Z
---

January 7th, 2026

### New Features

[#new-features](docId\:H6LM6Nv2Irfs683AgpFwH)

- **CMAB (Contextual Multi-Armed Bandit) Support** ([#94](https://github.com/optimizely/optimizely-flutter-sdk/pull/94))
  - Added `CmabConfig` class for CMAB initialization with configurable cache settings and custom prediction endpoints.
  - Added `decideAsync()` methods to `OptimizelyUserContext` for asynchronous CMAB decision-making.
  - New CMAB-specific decide options: `ignoreCmabCache`, `resetCmabCache`, `invalidateUserCmabCache`
- **Add Holdout support for feature experimentation.**
- **Add Multi-Region Support for Data Hosting.**

### Bug Fixes

[#bug-fixes](docId\:H6LM6Nv2Irfs683AgpFwH)

- **Nested Object Support in Event Metadata for Swift** ([#92](https://github.com/optimizely/optimizely-flutter-sdk/pull/92))
  - Enhanced event metadata handling to support complex nested objects in iOS/Swift.

[https://github.com/optimizely/optimizely-flutter-sdk/releases/tag/v3.4.0](https://github.com/optimizely/optimizely-flutter-sdk/releases/tag/v3.4.0)