Still prefer the stock Apple app.
And thats the point I made in my article "I'm No Taylor Swift But Here's My Open Letter To Time Cook!" Where I talked about some of Apples anti-competitive behavior thats killing the competition. This case is exactly the perfect example and I'll include it in my article. Not only did Apple take the whole idea from F.lux and implement it natively into the OS, but it also doesn't allow the same level access to the developers to implement it. It has also done it with fitness apps on the Apple Watch and will continue to do it. This ultimately kills small developers.
Apple should have bought out f.lux and implemented it or allowed them native access to implement it themselves. This is a feature that really doesn't need to be in Apples hands, and certain developers should have OS access to implement it and maintain it.