WatchOS3 Complication that launches App

These code changes are required:

func getSupportedTimeTravelDirections(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTimeTravelDirections) -> Void)
{
    handler([])
}


func getCurrentTimelineEntry(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTimelineEntry?) -> Void)
{
    if complication.family == .circularSmall
    {

        let template = CLKComplicationTemplateCircularSmallRingImage()
        template.imageProvider = CLKImageProvider(onePieceImage: UIImage(named: "Circular")!)
        let timelineEntry = CLKComplicationTimelineEntry(date: Date(), complicationTemplate: template)
        handler(timelineEntry)

    } else if complication.family == .utilitarianSmall
    {

        let template = CLKComplicationTemplateUtilitarianSmallRingImage()
        template.imageProvider = CLKImageProvider(onePieceImage: UIImage(named: "Utilitarian")!)
        let timelineEntry = CLKComplicationTimelineEntry(date: Date(), complicationTemplate: template)
        handler(timelineEntry)

    } else if complication.family == .modularSmall
    {

        let template = CLKComplicationTemplateModularSmallRingImage()
        template.imageProvider = CLKImageProvider(onePieceImage: UIImage(named: "Modular")!)
        let timelineEntry = CLKComplicationTimelineEntry(date: Date(), complicationTemplate: template)
        handler(timelineEntry)

    } else {

        handler(nil)

    }

}


func getLocalizableSampleTemplate(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTemplate?) -> Void)
{        
    switch complication.family
    {
        case .circularSmall:
            let image: UIImage = UIImage(named: "Circular")!
            let template = CLKComplicationTemplateCircularSmallSimpleImage()
            template.imageProvider = CLKImageProvider(onePieceImage: image)
            handler(template)
        case .utilitarianSmall:
            let image: UIImage = UIImage(named: "Utilitarian")!
            let template = CLKComplicationTemplateUtilitarianSmallSquare()
            template.imageProvider = CLKImageProvider(onePieceImage: image)
            handler(template)
        case .modularSmall:
            let image: UIImage = UIImage(named: "Modular")!
            let template = CLKComplicationTemplateModularSmallSimpleImage()
            template.imageProvider = CLKImageProvider(onePieceImage: image)
            handler(template)
        default:
            handler(nil)
    }
}

Plus you need to provide the images as assets in the extension.

Apple Watch 4 new graphic complications looks like this:

func getCurrentTimelineEntry(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTimelineEntry?) -> Void) {
    // Call the handler with the current timeline entry
    switch complication.family {
    case .graphicCorner:
        if #available(watchOSApplicationExtension 5.0, *) {
            let template = CLKComplicationTemplateGraphicCornerCircularImage()
            let image = UIImage(named: "Complication/Graphic Corner")!
            template.imageProvider = CLKFullColorImageProvider(fullColorImage: image)
            let timelineEntry = CLKComplicationTimelineEntry(date: Date(), complicationTemplate: template)
            handler(timelineEntry)
        } else {
            handler(nil)
        }
    case .graphicCircular:
        if #available(watchOSApplicationExtension 5.0, *) {
            let template = CLKComplicationTemplateGraphicCircularImage()
            let image = UIImage(named: "Complication/Graphic Circular")!
            template.imageProvider = CLKFullColorImageProvider(fullColorImage: image)
            let timelineEntry = CLKComplicationTimelineEntry(date: Date(), complicationTemplate: template)
            handler(timelineEntry)
        } else {
            handler(nil)
        }
    default:
        handler(nil)
    }
}

func getLocalizableSampleTemplate(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTemplate?) -> Void) {
    // This method will be called once per supported complication, and the results will be cached
    switch complication.family {
    case .graphicCorner:
        if #available(watchOSApplicationExtension 5.0, *) {
            let template = CLKComplicationTemplateGraphicCornerCircularImage()
            let image = UIImage(named: "Complication/Graphic Corner")!
            template.imageProvider = CLKFullColorImageProvider(fullColorImage: image)
            handler(template)
        } else {
            handler(nil)
        }
    case .graphicCircular:
        if #available(watchOSApplicationExtension 5.0, *) {
            let template = CLKComplicationTemplateGraphicCircularImage()
            let image = UIImage(named: "Complication/Graphic Circular")!
            template.imageProvider = CLKFullColorImageProvider(fullColorImage: image)
            handler(template)
        } else {
            handler(nil)
        }
    default:
        handler(nil)
    }
}