---
title: Add expo-updates to an existing project
description: Learn how to add expo-updates to an existing React Native project.
---

import { Terminal } from '~/ui/components/Snippet';
import { DiffBlock } from '~/ui/components/Snippet';

The `expo-updates` library fetches and manages updates received from a remote server. It supports [EAS Update](/eas-update/introduction), a hosted service that serves updates for projects using the `expo-updates` library.

> If you are creating a new project, we recommend using `npx create-expo-app --template bare-minimum` (or `yarn create expo-app --template bare-minimum`) instead of `npx react-native init` because it will handle the following configuration for you automatically. It includes the `expo-updates` [config plugin](/config-plugins/introduction/), which will handle the following steps for you.

## Installation

The `expo-updates` library requires that your project already has [Expo modules configured](/bare/installing-expo-modules). Be sure to install it before continuing.

To get started, install `expo-updates`:

<Terminal cmd={['$ npx expo install expo-updates']} />

Then, install pods:

<Terminal cmd={['$ npx pod-install']} />

Once installation is complete, apply the changes from the following diffs to configure `expo-updates` in your project.

## Configuration in JavaScript and JSON

Modify the `expo` section of **app.json**. (If you originally created your app using `npx react-native init`, you will need to add this section.)
The changes below add the updates URL to the Expo configuration.

> The example URL shown here is for use with a custom update server running on the same machine. When using EAS Update, the EAS CLI will set this URL correctly for the EAS Update service.

```diff app.json
 {
   "name": "MyApp",
-  "displayName": "MyApp"
+  "displayName": "MyApp",
+  "expo": {
+    "name": "MyApp",
+    "slug": "MyApp",
+    "ios": {
+      "bundleIdentifier": "com.MyApp"
+    },
+    "android": {
+      "package": "com.MyApp"
+    },
+    "runtimeVersion": "1.0.0",
+    "updates": {
+      "url": "http://localhost:3000/api/manifest"
+    }
+  }
 }
```

## Configuration for iOS

Add the file **Podfile.properties.json** to the **ios** directory:

```json ios/Podfile.properties.json
{
  "expo.jsEngine": "hermes"
}
```

Modify **ios/Podfile** to check for the JS engine configuration (JSC or Hermes) in Expo files:

```diff ios/Podfile
--- a/ios/Podfile
+++ b/ios/Podfile
@@ -2,6 +2,9 @@ require File.join(File.dirname(`node --print "require.resolve('expo/package.json
 require_relative '../node_modules/react-native/scripts/react_native_pods'
 require_relative '../node_modules/@react-native-community/cli-platform-ios/native_modules'

+require 'json'
+podfile_properties = JSON.parse(File.read(File.join(__dir__, 'Podfile.properties.json'))) rescue {}
+
 platform :ios, '13.0'
 prepare_react_native_project!

@@ -41,7 +44,7 @@ target 'MyApp' do
     # Hermes is now enabled by default. Disable by setting this flag to false.
     # Upcoming versions of React Native may rely on get_default_flags(), but
     # we make it explicit here to aid in the React Native upgrade process.
-    :hermes_enabled => flags[:hermes_enabled],
+    :hermes_enabled => podfile_properties['expo.jsEngine'] == nil || podfile_properties['expo.jsEngine'] == 'hermes',
     :fabric_enabled => flags[:fabric_enabled],
     # Enables Flipper.
     #

```

Add the **Supporting** directory containing **Expo.plist** to your project in Xcode with the following content, to match the content in **app.json**:

```xml Expo.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>EXUpdatesCheckOnLaunch</key>
    <string>ALWAYS</string>
    <key>EXUpdatesEnabled</key>
    <true/>
    <key>EXUpdatesLaunchWaitMs</key>
    <integer>0</integer>
    <key>EXUpdatesRuntimeVersion</key>
    <string>1.0.0</string>
    <key>EXUpdatesURL</key>
    <string>http://localhost:3000/api/manifest</string>
  </dict>
</plist>
```

## Configuration for Android

Modify **android/app/build.gradle** to check for the JS engine configuration (JSC or Hermes) in Expo files:

```diff android/app/build.gradle
--- a/android/app/build.gradle
+++ b/android/app/build.gradle
@@ -52,6 +52,11 @@ react {
     // hermesFlags = ["-O", "-output-source-map"]
 }

+// Override `hermesEnabled` by `expo.jsEngine`
+ext {
+  hermesEnabled = (findProperty('expo.jsEngine') ?: "hermes") == "hermes"
+}
+
 /**
  * Set this to true to create four separate APKs instead of one,
  * one for each native architecture. This is useful if you don't
```

Modify **android/app/src/main/AndroidManifest.xml** to add the `expo-updates` configuration XML so that it matches the contents of **app.json**:

```diff android/app/src/main/AndroidManifest.xml
--- a/android/app/src/main/AndroidManifest.xml
+++ b/android/app/src/main/AndroidManifest.xml
@@ -9,6 +9,11 @@
       android:roundIcon="@mipmap/ic_launcher_round"
       android:allowBackup="false"
       android:theme="@style/AppTheme">
+      <meta-data android:name="expo.modules.updates.ENABLED" android:value="true"/>
+      <meta-data android:name="expo.modules.updates.EXPO_RUNTIME_VERSION" android:value="@string/expo_runtime_version"/>
+      <meta-data android:name="expo.modules.updates.EXPO_UPDATES_CHECK_ON_LAUNCH" android:value="ALWAYS"/>
+      <meta-data android:name="expo.modules.updates.EXPO_UPDATES_LAUNCH_WAIT_MS" android:value="0"/>
+      <meta-data android:name="expo.modules.updates.EXPO_UPDATE_URL" android:value="http://localhost:3000/api/manifest"/>
       <activity
         android:name=".MainActivity"
         android:label="@string/app_name"
```

Add the Expo runtime version string key to **android/app/src/main/res/values/strings.xml**:

<DiffBlock source="/static/diffs/expo-update-strings-xml.diff" />

## Next steps

See more information about usage in the [`expo-updates` README](https://github.com/expo/expo/tree/main/packages/expo-updates/README.md).

See [this guide](/eas-update/build-locally/) for trying out EAS Update with a local build.

To start trying out EAS Update with EAS Build, see the [EAS Update "Getting Started" guide](/eas-update/getting-started/).

It is also possible to use `expo-updates` with a custom server that implements the [Expo Updates protocol](/technical-specs/expo-updates-1/); see the [`custom-expo-updates-server` README](https://github.com/expo/custom-expo-updates-server#readme).