---
title: Swift-SDK - 3.3.0
slug: feature-experimentation/release-notes/swift-sdk-3-3-0
docTags: 
createdAt: 2026-07-20T15:44:19.464Z
---

\## 3.3.0
March 11, 2020

This release includes an enhancement of SDK initialization API to enable SDK updated on cached datafile change. It also fixes known bugs.

\### New Features
\* Add an option for **synchronous** initialization to enable SDK immediately updated when a new datafile is cached. Unless this feature is enabled, by default, the cached datafile will be used only when the SDK re-starts in the next session. Note that this option is for **synchronous** initialization only. (\[#297]\([https://github.com/optimizely/swift-sdk/pull/297](https://github.com/optimizely/swift-sdk/pull/297)))

\`\`\`
// enable SDK update when a new datafile is cached
optimizelyClient.start(datafile: data, doUpdateConfigOnNewDatafile: true)

// by default, this feature is disabled
optimizelyClient.start(datafile: data)
\`\`\`

\### Bug Fixes
\* When a **synchronously**-initialized SDK enables background datafile polling and its datafile was changed in the server, the new datafile is cached but SDK is not dynamically updated. (\[#297]\([https://github.com/optimizely/swift-sdk/pull/297](https://github.com/optimizely/swift-sdk/pull/297)))
\* When background datafile polling is enabled and app goes to background and comes back to foreground after some delays, datafile fetching is called multiple times back-to-back. (\[#301]\([https://github.com/optimizely/swift-sdk/pull/301](https://github.com/optimizely/swift-sdk/pull/301)))
\* NotificationCenter can cause crashes when multiple threads add/call listeners simultaneously. (\[#304]\([https://github.com/optimizely/swift-sdk/pull/304](https://github.com/optimizely/swift-sdk/pull/304)))

[https://github.com/optimizely/swift-sdk/releases/tag/v3.3.0](https://github.com/optimizely/swift-sdk/releases/tag/v3.3.0)