On my recent trip to Hong Kong with Singapore Airlines, I used Singapore Airlines mobile application to test its function. Singapore Airlines mobile application has been improving over time and it is very polished and functional.
Once application is executed, you will see this. You will be able to see your KrisFlyer status and miles.
When you scroll down on landing screen with trip information, you will see this. From this screen you can manage Check-in.
On left hand corner, you can select menu for more functions.
This application is a good complement to their website and it is powered by Amadeus which is a widely used system in airlines for ticketing.
This application is available for FREE without ADs on Android Google Play and iOS App Store.