# Application Lifecycle Tracking in Mobile SDKs


The RudderStack [Android (Kotlin)]({{< ref "sources/event-streams/sdks/kotlin-sdk/" >}}) and [iOS (Swift)]({{< ref "sources/event-streams/sdks/swift-sdk/" >}}) SDKs automatically track the following lifecycle events when you use the lifecycle tracking feature in your app:

- `Application Installed`
- `Application Updated`
- `Application Opened`
- `Application Backgrounded`

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With the application lifecycle tracking feature, you can automatically capture user's app usage behavior and get insights into their behaviour and app engagement patterns.
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## Manage lifecycle tracking

Note that the lifecycle tracking feature is enabled in the mobile SDKs by default. To turn it off, set `trackApplicationLifecycleEvents` to `false` / `NO` (in case of Objective-C) in the `Configuration` object during the SDK initialization, as shown:

{{< tabs tabTotal="2" >}}
{{% tab tabName="Android (Kotlin)" %}}
```kotlin
analytics = Analytics(
    configuration = Configuration(
        trackApplicationLifecycleEvents = false,
        writeKey = BuildConfig.WRITE_KEY,
        application = application,
        dataPlaneUrl = BuildConfig.DATA_PLANE_URL,
    )
)
```

The corresponding Java snippet is shown below:

```java
Configuration configuration = new ConfigurationBuilder(this, "WRITE_KEY", "DATA_PLANE_URL")
        .setTrackApplicationLifecycleEvents(true)
        .build();

analytics = new JavaAnalytics(configuration);
```

{{% /tab %}}
{{% tab tabName="iOS (Swift)" %}}
```swift
analytics = Analytics(
    configuration: Configuration(
        writeKey: "WRITE_KEY",
        dataPlaneUrl: "DATA_PLANE_URL",
        trackApplicationLifecycleEvents: false
    )
)
```

The corresponding Objective-C snippet is shown below:

```objectivec
RSSConfigurationBuilder *builder = [[RSSConfigurationBuilder alloc] 
		initWithWriteKey:@"WRITE_KEY"
		dataPlaneUrl:@"DATA_PLANE_URL"];

[builder setTrackApplicationLifecycleEvents:NO];

analytics = [[RSSAnalytics alloc] initWithConfiguration:[builder build]];
```
{{% /tab %}}
{{< /tabs >}}

## Lifecycle events

This section covers the different application lifecycle events tracked by the SDK.

### Application Installed

The `Application Installed` event is triggered when the user opens the app for the first time after installation.

The SDK also captures the following properties while tracking this event:

| Property | Data type | Description |
| :----| :----| :-----|
| `version`  | String | App's version name. |
| `build` | Long | App's build number. |

### Application Updated

The `Application Updated` event is triggered when the user opens the app for the first time **after** updating it.

The SDK also captures the following properties while tracking this event:

| Property | Data type | Description |
| :----| :----| :-----|
| `version`  | String | App's version name. |
| `build` | Long | App's build number. |
| `previous_version` | String | App's version name before the update. |
| `build` | Long | App's build number before the update. |

### Application Opened

The `Application Opened` event is triggered when the user opens the app, either as a fresh launch or from the background.

The SDK also captures the following properties while tracking this event:

| Property | Data type | Description |
| :----| :----| :-----|
| `version`  | String | App's current version name. <br /><br />**Note**: This property is tracked only for a fresh app launch. |
| `from_background` | Boolean | Set to `true` if the app was opened from the background, set to `false`  otherwise. |

### Application Backgrounded

The `Application Backgrounded` event is triggered whenever the app is backgrounded. Note that this event **does not** contain any additional properties.

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