## TL;DR

Maintainers switched the dependency (PR #666) and shipped it in optimizely-sdk 4.6.0, with react-sdk 2.6.0 following.

## Steps

1. Issue optimizely/javascript-sdk#663 (closed, 9 comments): the SDK depended on @react-native-community/async-storage, which was deprecated; mixing it with @react-native-async-storage/async-storage in one Expo 40+ app broke the build. Maintainers switched the dependency (PR #666) and shipped it in optimizely-sdk 4.6.0, with react-sdk 2.6.0 following.

2. If your React Native app breaks because it has both async-storage packages, the fix is on the SDK side: upgrade @optimizely/optimizely-sdk to 4.6.0 or later (or @optimizely/react-sdk to 2.6.0+), which moved to @react-native-async-storage/async-storage. You cannot mix the old community package and the new one in the same project, so make sure your own code imports the new package too.

## When to use

You are seeing this: Issue optimizely/javascript-sdk#663 (closed, 9 comments): the SDK depended on @react-native-community/async-storage, which was deprecated; mixing it with @react-native-async-storage/async-storage in one Expo 40+ app broke the build. Use this skill when you run into "React Native Expo 40+ breaks on the deprecated async-storage package".

## When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

## Versions

Versions mentioned in the source: optimizely-sdk 4.6.0, react-sdk 2.6.0. If you are on something much newer or older, the details may have shifted.

## Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.