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# serviceSubscriberCellularProvidersDidUpdateNotifier

A block dispatched when there are updates to the user’s cellular provider information for any service.

```
var serviceSubscriberCellularProvidersDidUpdateNotifier: ((String) -> Void)? { get set }
```

## Discussion

The block object executes on the default priority global dispatch queue when the user’s cellular provider information changes. This occurs, for example, if a user swaps the device’s SIM card with one from another provider, while your app is running.

To handle changes in cellular service provider information, define a block in your app and assign it to this property. Implement the block to support being called from any context. To get the new information, use the <doc://com.apple.documentation/documentation/Foundation/NSString> (which contains the identifier of the service whose information has changed) as the key into [`serviceSubscriberCellularProviders`](/documentation/CoreTelephony/CTTelephonyNetworkInfo/serviceSubscriberCellularProviders).

---

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