I currently have two versions of an application - a free version with ads and a paid version with no ads. I've had a ton of requests from users to ease the transition from the free version to the paid version, and I'd really like to do that.
One way of doing it is to simply remove the free version, make the paid version free and then add in-app purchasing to remove ads.
My only concern is this: How will I be able to determine which of my users have previously purchased the application? Is it possible to do with Google Play licensing?