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# CLKComplicationServer

An object that manages the active complications for an app.

```
class CLKComplicationServer
```

## Overview

Don’t create instances of this class directly. Instead, use the shared object to fetch information about your active complications and to invalidate or extend the data for a specific complication. You can also use it to get information about the minimum and maximum dates for which you need to provide data to support Time Travel.

## Topics

### Getting the Complication Server

[`sharedInstance()`](/documentation/ClockKit/CLKComplicationServer/sharedInstance())

Returns the shared complication server.

### Getting the Active Complications

[`activeComplications`](/documentation/ClockKit/CLKComplicationServer/activeComplications)

The active complications for the current app.

### Updating Your Timeline Data

[`reloadTimeline(for:)`](/documentation/ClockKit/CLKComplicationServer/reloadTimeline(for:))

Invalidates your existing timeline data and triggers an update session to reload it.

[`extendTimeline(for:)`](/documentation/ClockKit/CLKComplicationServer/extendTimeline(for:))

Asks the system to extend the data in your complication’s timeline.

### Updating Complication Types

[`reloadComplicationDescriptors()`](/documentation/ClockKit/CLKComplicationServer/reloadComplicationDescriptors())

Reloads the complication descriptors from the complication data source.

### Receiving Change Notifications

[`CLKComplicationServerActiveComplicationsDidChangeNotification`](/documentation/ClockKit/CLKComplicationServerActiveComplicationsDidChangeNotification)

Posted when the set of active complications changes.

### Getting the Time Travel Boundaries

[`earliestTimeTravelDate`](/documentation/ClockKit/CLKComplicationServer/earliestTimeTravelDate)

The earliest Time Travel date for which you should provide data.

[`latestTimeTravelDate`](/documentation/ClockKit/CLKComplicationServer/latestTimeTravelDate)

The latest date supported by Time Travel.


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