How to do swift availability checking on watchOS 3

I'm having an interesting problem with watchOS 3 and watchOS 2. In my ComplicationController I want to support both watchOS 3 and watchOS 2. When creating the complication templates I'm checking if the user is running watchOS 3. If he is I will allow an .ExtraLarge complication to be used, otherwise this option is not available.

I'm using the #available syntax, but the app fails to even launch on watchOS 2 because of a missing framework. Here is my code:

if #available(watchOSApplicationExtension 3.0, *) {
   if complicationFamily == .ExtraLarge {
      let extraLarge = CLKComplicationTemplateExtraLargeSimpleText()
      extraLarge.textProvider = simpleTextProvider

      return extraLarge
   } else {
      return nil
   }
} else {
   return nil
}

When I run on watchOS 2 this is the error I get:

dyld: Symbol not found: _OBJC_CLASS_$_CLKComplicationTemplateExtraLargeSimpleText
  Referenced from: /Users/asdf/Library/Developer/CoreSimulator/Devices/48D00565-3BA5-4851-B249-5818BA060716/data/Containers/Bundle/Application/1ACF1C41-9D9E-4AB6-9D49-767A067AE968/WatchKit App.app/PlugIns/WatchKit Extension.appex/WatchKit Extension
  Expected in: /Library/Developer/CoreSimulator/Profiles/Runtimes/watchOS 2.2.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/ClockKit.framework/ClockKit

Has anyone else had issues deploying to both watchOS 3 and watchOS 2?

Solution

I figured it out with help from a post on the Apple Developer Forums. I needed to add the ClockKit.framework to the linked binaries and set its status to Optional. Now everything works as expected on watchOS 2.

Here's the post: https://forums.developer.apple.com/thread/61712