Has there been any update on this ? I've created two projects, one for ClockKit and one for WidgetKit based complications. Both projects are single target (no extension delegate, only app delegate) and SwiftUI.
My observations
ClockKit
transferCurrentComplicationUserInfo wakes up the watch app even if the user has previously terminated it and the reveive user info delegate method is called.
WidgetKit
transferCurrentComplicationUserInfo does NOT wake the watchOS app, and the delegate method of received user info is called only after the app is opened by the user.
This is a shame for WidgetKit complications not to be production ready yet...