---
title: CSharp-SDK - 4.3.0
slug: feature-experimentation/release-notes/csharp-sdk-4-3-0
docTags: 
createdAt: 2026-07-20T15:45:04.725Z
---

## 4.3.0

May 11, 2026

### New Features

**Feature Rollout**: Added support for Feature Rollouts, a new experiment type combining Targeted Delivery simplicity with A/B test measurement capabilities. Feature Rollouts enable progressive rollouts with full impact analytics, metric tracking, and confidence intervals. See [Feature Rollout docs](docId\:FYbuu0asBt5htNNrEp235) for more information.

- Add Feature Rollout support ([#400](https://github.com/optimizely/csharp-sdk/pull/400))
- Remove experiment type validation from config parsing ([#402](https://github.com/optimizely/csharp-sdk/pull/402))
- Documentation improvement ([#399](https://github.com/optimizely/csharp-sdk/pull/399))
- Event retry adjustment ([#398](https://github.com/optimizely/csharp-sdk/pull/398))

[https://github.com/optimizely/csharp-sdk/releases/tag/v4.3.0](https://github.com/optimizely/csharp-sdk/releases/tag/v4.3.0)